Lateral thinking: open practice pack #################################### 25 untimed puzzles on a difficulty 1–5 ladder. Pack: puzzles-lateral-thinking Source: puzzles Pack version: v1 Worksheet items: 25 Authored hints: 25 Worked explanations: 25 ! Puzzles are an untimed educational and entertainment activity. They are not a clinical, diagnostic, standardized, or professionally recognized assessment. Solving puzzles here does not produce an IQ score and cannot be used for Mensa qualification, diagnosis, giftedness identification, educational placement, employment selection, disability applications, accommodations, legal matters, or medical decisions. Puzzle items are never used as unseen scored questions in any Novus Learn assessment. ! The answer key and worked explanations in this file belong only to this public, untimed educational practice source. No active aptitude suite or Novus Reasoning Challenge answer key is ever included in any download. Learner worksheet ================= Work through these at your own pace. Nothing here is timed and nothing is scored. Read every fact before you commit. In this category the detail that reads as scenery is often the one that decides it. Check your answer, then read the explanation even when you were right: it names the assumption that made the situation look impossible, and that is the part which transfers to the next puzzle. Choose one answer for each item. Keep the authored hints, answer key, and worked explanations separate until you are ready to check your work. Difficulty 1 ------------ Start here and establish the method before moving up the ladder. 1. puz-lateral-thinking-01: The ring on the table ------------------------------------------------- Difficulty: Difficulty 1 What is Priya telling Owen about? A note left on a shared kitchen door. 1. Priya left a note on the kitchen door: “There is a ring on the table and it is yours.” 2. Her housemate Owen owns no jewellery and has lost nothing. 3. Owen drank cocoa at the kitchen table last night and did not use a mat. 4. The table is bare varnished wood, and Priya polishes it every Saturday. 5. Owen's phone shows no missed calls. - A. A piece of jewellery Owen dropped and forgot about. - B. A circle Priya drew on the table to show where to sit. - C. A pale circular mark left on the varnish by his mug. - D. A telephone call Owen missed while he was out. Your answer: ______ 2. puz-lateral-thinking-02: The cup that went cold -------------------------------------------------- Difficulty: Difficulty 1 Why was the tea cold when Ines sat back down? One afternoon, told in the order it happened. 1. Ines poured a fresh, steaming cup of tea and set it on her desk. 2. The doorbell rang and she went to answer it. 3. When she sat back down the tea was stone cold. 4. Nobody else entered the flat, nothing was added to the cup, and the heating was on all afternoon. 5. The caller was a neighbour whose boiler had failed; Ines helped her ring an engineer and wait for him. - A. The errand at the door lasted hours, so the tea had ample time to cool. - B. The heating went off while she was out of the room. - C. She poured the tea from a pot that had already gone cold. - D. The neighbour swapped the cup for a cold one as a joke. Your answer: ______ 3. puz-lateral-thinking-03: Six posts, five people -------------------------------------------------- Difficulty: Difficulty 1 How can the minutes be accurate? An extract from a committee meeting. 1. The choir committee has six named posts but only five people sit on it. 2. The minutes read: “The treasurer passed the accounts to the librarian for filing.” 3. During the meeting nobody left their seat and no papers were handed across the table. 4. The accounts are a paper ledger, and there is no computer in the room. 5. The minutes are accurate and nothing has been left out. - A. The accounts were emailed rather than handed over. - B. The minutes record something that was only planned, not done. - C. The librarian was absent and collected the accounts later. - D. One person holds both posts, so the handover happened in one pair of hands. Your answer: ______ 4. puz-lateral-thinking-04: The heaviest book on the trolley ------------------------------------------------------------ Difficulty: Difficulty 1 Why does the librarian want the heaviest book on the trolley? An afternoon of moving boxes in a closed library. 1. The library is closed to readers this afternoon and boxes are being carried into the store room. 2. The librarian asks a volunteer to fetch the heaviest book on the trolley. 3. The fire door to the store room swings shut on its own, so the volunteer must put the boxes down every time to open it. 4. Nothing may be screwed or taped to the door or to the walls. 5. There is no draught in the building and every window is shut. - A. Because the heaviest book is the one due to be catalogued first. - B. To hold the self-closing door open while the boxes are carried through. - C. To weigh down loose paper in a draught. - D. To test whether the trolley's shelf will take the load. Your answer: ______ 5. puz-lateral-thinking-05: The new neighbour in flat four ---------------------------------------------------------- Difficulty: Difficulty 1 How can both diary entries be accurate? Two entries from the same week of a diary. 1. One flat in Dana's building, flat four, came free in the spring and was taken in May. 2. Monday's entry: “Met the new neighbour from flat four, a tall man who plays the trumpet.” 3. Thursday's entry: “Met the new neighbour from flat four, a short woman who keeps bees.” 4. Both entries are accurate, and Dana never repeats herself. 5. Nobody moved in or out of the building between Monday and Thursday. - A. Flat four is home to two people, so there are two new neighbours. - B. The man moved out and the woman replaced him within the week. - C. Dana met the same person twice and misremembered the second meeting. - D. One entry describes a visitor rather than a resident. Your answer: ______ Difficulty 2 ------------ Continue in order; use the worked explanations from earlier rungs when needed. 6. puz-lateral-thinking-06: Out to the weir and back ---------------------------------------------------- Difficulty: Difficulty 2 Why was the return trip fifteen minutes quicker? An afternoon's rowing on a river. 1. The boathouse and the weir sit on the same river, two kilometres apart. 2. Marek rows out to the weir in forty minutes. 3. He rows back to the boathouse in twenty-five minutes. 4. He pulled just as hard in both directions, and the air was still all afternoon. 5. A stick dropped off the boathouse jetty drifts steadily away from the weir. - A. He was tired on the way out and warmed up on the way back. - B. The return route was shorter than the outward one. - C. He rowed against the current going out and with it coming back. - D. A tailwind pushed him home. Your answer: ______ 7. puz-lateral-thinking-07: The voice in the empty hall ------------------------------------------------------- Difficulty: Difficulty 2 What is the caretaker hearing at six o'clock each evening? Five evenings in a locked office building. 1. After half past five the caretaker is the only person in the building, and the outside doors are locked. 2. At six o'clock each evening she hears a woman's voice call out from the entrance hall. 3. The voice says exactly the same six words at exactly the same minute every evening. 4. She has searched the hall each time and found nobody, and nobody is playing a trick on her. 5. Last month an accessibility system was fitted, with speakers in the ceiling of the entrance hall. - A. A colleague calling down the stairwell from the floor above. - B. A timed recorded announcement played through the new ceiling speakers. - C. An echo of the caretaker's own voice returning from the stairs. - D. A radio left switched on in a nearby office. Your answer: ______ 8. puz-lateral-thinking-08: Three tins and three lids ----------------------------------------------------- Difficulty: Difficulty 2 Why does the tin under the label marked Rice contain sugar? A store cupboard, the morning after a clean. 1. The cupboard holds three identical tins whose printed labels (Flour, Sugar, Rice) are stuck to the lids. 2. Yesterday a helper emptied, washed and dried all three tins, refilled them from the sacks, and put the lids back on. 3. The sacks are open at the top and their contents are plainly visible. 4. The helper checked each tin against its label as he filled it. 5. This morning the cook lifted the lid marked Rice and found sugar underneath. 6. Nothing was taken, nobody moved a label, and nobody played a trick. - A. The helper poured each sack into the wrong tin. - B. Sugar and rice look alike, so the cook has misread what she found. - C. The sacks in the store room are themselves mislabelled. - D. The labels are on the lids, and the lids went back onto different tins. Your answer: ______ 9. puz-lateral-thinking-09: The cake and the photograph ------------------------------------------------------- Difficulty: Difficulty 2 How can Rosa's account and the photograph both be accurate? One party, described twice. 1. Rosa's account of the party: “We sang, we cut the cake, and Theo arrived.” 2. Rosa's account is truthful and complete. 3. An unaltered photograph taken at that party shows Theo beside the cake, candles lit and the cake whole. 4. There was one cake and it was cut once. - A. Rosa listed three things that happened without claiming that order. - B. There were two cakes, one of them still uncut in the photograph. - C. The photograph was taken at a different gathering. - D. Rosa is mistaken about Theo having been there at all. Your answer: ______ 10. puz-lateral-thinking-10: Four seconds to the summit ------------------------------------------------------- Difficulty: Difficulty 2 What are the two of them looking at? A visitor and a guide, standing side by side. 1. A visitor points at the church and asks how long it takes to walk from there to the top of the fell. 2. The guide says “about four seconds”, and means it. 3. From where they stand, both can see the church, the lane, the river and the whole fell at once without turning their heads. 4. Neither is looking at a screen, a photograph or a printed map, and neither is joking. 5. The guide can reach out and touch the summit. - A. A photograph of the valley hanging in the visitor centre. - B. The real valley seen from a high viewpoint above it. - C. A scale model of the valley laid out in the grounds. - D. A cable car that carries walkers to the summit. Your answer: ______ 11. puz-lateral-thinking-11: Eight doors, six tenancies ------------------------------------------------------- Difficulty: Difficulty 2 How can there be eight street doors but only six tenancies? A landlord and a letting agent, both telling the truth. 1. Eight doors open onto the street along the front of the block. 2. Every flat in the block is let, and none is empty. 3. The letting agent's file lists six tenancies and is complete and correct. 4. No tenant rents two flats, and no flat is split between two tenancies. 5. As well as flats, the block contains a bin store and a stairwell to the upper floors, each reached from the street. - A. Two flats are empty and therefore unlisted. - B. Two of the doors serve the bin store and the shared stairwell, not homes. - C. Two tenants each rent a second flat. - D. The agent's file is missing two tenancies. Your answer: ______ Difficulty 3 ------------ Continue in order; use the worked explanations from earlier rungs when needed. 12. puz-lateral-thinking-12: The shed that lights itself -------------------------------------------------------- Difficulty: Difficulty 3 Two explanations are on the table: someone is getting into the shed at night, or the shed is lighting itself. Which one fits every fact? An allotment shed, five mornings running. 1. Farhan locks the shed at dusk with the light off and finds it lit when he arrives at seven the next morning. 2. Only Farhan and his neighbour Delia hold keys, and Delia has been in another country for three weeks. 3. The shed's one window is painted over and does not open. 4. Every morning the rocker switch by the door is still in the off position, and no timer is fitted to it. 5. A month ago Farhan replaced the bulb with a motion-sensing one, and mice have been getting in under the door. - A. Delia is letting herself in early each morning. - B. The rocker switch is faulty and closes on its own overnight. - C. Light from the lane shows through the shed window. - D. Mice moving about under the door trigger the motion-sensing bulb. Your answer: ______ 13. puz-lateral-thinking-13: The Monday copier ---------------------------------------------- Difficulty: Difficulty 3 Why does the copier jam only on Monday mornings? A library photocopier with a very regular fault. 1. The copier jams repeatedly on Monday mornings and works normally from Monday lunchtime until Friday closing. 2. The same staff use it, with the same paper, and it copies roughly the same number of pages every day. 3. The building is unheated from Friday evening until eight o'clock on Monday morning. 4. Paper is stored in an open rack against an outside wall beside the machine. 5. An engineer has stripped the machine twice and found no mechanical fault. - A. The paper takes up damp over the cold weekend and feeds badly until the room warms. - B. Monday is the machine's heaviest morning, so it overheats. - C. A mechanical fault shows itself only under load. - D. The weekend cleaners refill the tray with the wrong paper. Your answer: ______ 14. puz-lateral-thinking-14: The crate that would not fit --------------------------------------------------------- Difficulty: Difficulty 3 How did the crate reach the fifth floor? A delivery to a fifth-floor office. 1. The crate is a rigid box 2.05 metres long, 0.4 metres wide and 0.4 metres deep. 2. The lift car measures 2.00 metres wide, 2.00 metres deep and 2.00 metres high. 3. The staircase turns so sharply that nothing longer than 1.6 metres can be carried up it at any angle. 4. The crate arrived on the fifth floor undamaged, unopened and unbent. 5. There is no hoist, no crane, and no way in from outside the building. - A. It was carried up the stairs at an angle. - B. It stood corner to corner in the lift, whose floor diagonal is nearly three metres. - C. It was taken apart and rebuilt on the landing. - D. It was lifted in through a window from outside. Your answer: ______ 15. puz-lateral-thinking-15: The text that never arrived -------------------------------------------------------- Difficulty: Difficulty 3 What does the missing text message establish? A surgery appointment that nobody has a record of. 1. The surgery sends every patient a text on the evening before an appointment, without exception. 2. Priya's phone has kept every message it has received this year and she has deleted none. 3. There is no message from the surgery about Tuesday. 4. Her phone had signal all week and received other messages on Monday evening. 5. Priya arrived on Tuesday and was told there was no appointment in her name. - A. Her phone failed to receive the message. - B. She noted the wrong day and the appointment is later in the week. - C. On Monday evening the surgery held no Tuesday appointment in her name. - D. The surgery cancelled the appointment on Tuesday morning. Your answer: ______ 16. puz-lateral-thinking-16: The yellowing tomatoes --------------------------------------------------- Difficulty: Difficulty 3 What most likely damaged the four plants? Eight tomato plants and one new bottle of feed. 1. Sana fed eight tomato plants with a new feed on the first of June, at the strength printed on the bottle. 2. Four of the plants are in her greenhouse and four are in an outdoor bed. 3. By the tenth of June the four in the greenhouse had yellowed; the four outdoors were untouched. 4. The greenhouse's automatic vent jammed shut on the last day of May and was freed on the eleventh of June. 5. She has grown tomatoes in the same greenhouse soil for nine years without losing a plant. - A. The new feed, applied more strongly than the label allows. - B. A disease that spreads only under glass. - C. Nine years of the same soil finally running out of goodness. - D. The greenhouse overheating while its vent was jammed shut. Your answer: ______ 17. puz-lateral-thinking-17: The cafe and the lost property ----------------------------------------------------------- Difficulty: Difficulty 3 What best explains the two totals rising and falling together? Two years of records from a leisure centre. 1. On days the cafe takes more than four hundred pounds, lost property receives twelve or more items. 2. On quiet cafe days it receives fewer than four. 3. Almost every item handed in is a towel, a pair of goggles or a swimming cap. 4. School galas and lesson blocks run on the same days the cafe is busiest. 5. The two totals have risen and fallen together for two years. - A. Cafe customers are more careless than other visitors. - B. Both totals rise when more people swim, so the swimmer count drives each. - C. Buying food makes swimmers hurry and forget their kit. - D. Staff hand in more items on days the cafe keeps them busy. Your answer: ______ Difficulty 4 ------------ Continue in order; use the worked explanations from earlier rungs when needed. 18. puz-lateral-thinking-18: The docket signed at twenty to eleven ------------------------------------------------------------------ Difficulty: Difficulty 4 Which fact could be deleted without weakening the conclusion that Salim signed? Six facts gathered about one delivery. 1. The delivery docket was signed inside the building at 10:40 on Wednesday. 2. Only four people can get into the building: Nina, Piotr, Ruth and Salim. 3. Nina was on a train between 10:00 and 11:30 on Wednesday. 4. Piotr broke his writing wrist in April and has signed nothing since. 5. Ruth's badge shows she first entered the building at 11:05 on Wednesday. 6. Salim's badge shows he was in the building from 08:30 on Wednesday. - A. Salim's badge record for Wednesday morning. - B. The list of who can get into the building. - C. Nina's train journey. - D. Piotr's broken wrist. Your answer: ______ 19. puz-lateral-thinking-19: The minibus that stayed put -------------------------------------------------------- Difficulty: Difficulty 4 Why did the driver refuse to set off? A school trip, ready to leave. 1. The minibus is licensed to carry sixteen passengers plus the driver. 2. Every child on the trip was given exactly one packed lunch. 3. The caterer delivered eighteen packed lunches; all were handed out and none was left over. 4. Two adult helpers are travelling as well, and each was given a packed lunch too. 5. The driver brings his own food and does not count as a passenger. 6. The driver counted heads at the door and refused to set off. - A. There are eighteen children, two more than the bus may carry. - B. There are sixteen children and the bus is exactly full. - C. There are eighteen passengers for sixteen passenger seats. - D. Two packed lunches are missing, so two children have none. Your answer: ______ 20. puz-lateral-thinking-20: The propped fire door -------------------------------------------------- Difficulty: Difficulty 4 What best explains both the wet floor and the scattered papers? A reading room, found after lunch. 1. The librarian comes back from lunch to find the reading room's fire door propped open with a chair. 2. There is a wet patch on the floor by that door and papers scattered across the room. 3. It has not rained for nine days and the ground outside is dry. 4. The corridor's water cooler has been moved out of its alcove and now stands just outside the fire door. 5. The window at the far end of the reading room is wedged open all summer. - A. Rain blew in through the propped-open fire door. - B. A pipe above the ceiling has been dripping onto the floor. - C. Someone searched the room and left in a hurry. - D. A water cooler spilt as it was moved out, and the through-draught scattered the papers. Your answer: ______ 21. puz-lateral-thinking-21: The bicycle and the locked rack ------------------------------------------------------------ Difficulty: Difficulty 4 Which stated fact makes the theft possible? A bicycle rack, Tuesday evening to Wednesday morning. 1. On Tuesday the owner locked her bicycle to the rack with a rigid D-lock and walked away. 2. On Wednesday morning the frame, the front wheel and the saddle are gone. 3. The D-lock is still closed around the rack's rail, with the rear wheel hanging inside it. 4. The lock shows no cut marks and its key has not left her pocket. 5. The rear wheel is held to the frame by a quick-release lever that opens by hand. 6. The rack is bolted down, undamaged, and nothing else in it has been touched. - A. The rear wheel is held on by a lever that opens by hand. - B. The key has never left the owner's pocket. - C. The lock's shackle shows no cut marks. - D. The lock is still closed and still around the rail. Your answer: ______ 22. puz-lateral-thinking-22: The note about the bag --------------------------------------------------- Difficulty: Difficulty 4 What must be true about the flatmate? One evening, minute by minute. 1. Yusuf left his bag on the chair by the window of a cafe he had never visited before, at half past five, and walked straight home, arriving at six. 2. He spoke to nobody on the way and sent no messages. 3. A note in his flatmate's handwriting was on the kitchen table when he arrived, saying his bag was on the chair by the cafe window. 4. The flatmate was in the flat until quarter to six, then went out and has not been back. 5. The flat has no telephone and her mobile has been switched off since noon. - A. Yusuf telephoned the flat and has forgotten doing so. - B. Someone from the cafe rang the flat to report the bag. - C. The note was written after Yusuf reached home. - D. She saw the bag on that chair herself, between half past five and quarter to six. Your answer: ______ Difficulty 5 ------------ Continue in order; use the worked explanations from earlier rungs when needed. 23. puz-lateral-thinking-23: Rows and chairs -------------------------------------------- Difficulty: Difficulty 5 How many rows of chairs are there? One exchange between two people who each hold half the information. 1. A hall is laid out in equal rows of chairs; the number of rows and the number of chairs in each row are both at least two. 2. Everyone present knows the total number of chairs is either twelve or eighteen. 3. Petra has been told the number of rows, and nobody else has been told it. 4. Quinn has been told the number of chairs in each row, and nobody else has been told it. 5. Petra says: “I cannot work out the total.” 6. Quinn replies: “Before you spoke I could not work it out either, but now I can.” 7. Both speak truthfully, and each knows everything above. - A. Two rows. - B. Three rows. - C. Six rows. - D. Nine rows. Your answer: ______ 24. puz-lateral-thinking-24: The key that never left its box ------------------------------------------------------------ Difficulty: Difficulty 5 Which assumption must be dropped for every fact to hold together? One Saturday at the village hall. 1. The hall has one key; it hangs in a box on the post office wall and every borrower signs it out and back in. 2. The hall was unlocked at nine on Saturday morning and locked again at ten at night. 3. The book records the key out at ten to nine and back at twenty past nine, then out again at twenty-five to ten in the evening and back at twenty past ten. 4. The postmaster is certain the key never left its box on Saturday: he looked at half past nine, at one o'clock and at six o'clock, and it was hanging there each time. 5. No copy exists, the lock was not forced or changed, and the doors cannot be locked or unlocked without the key. - A. That the postmaster's three observations were accurate. - B. That checks at three moments show where the key was in between. - C. That the signing-out book is complete and honestly kept. - D. That the hall was in use for the whole of Saturday. Your answer: ______ 25. puz-lateral-thinking-25: The message on the shed door --------------------------------------------------------- Difficulty: Difficulty 5 Who wrote the note in the shed? A locked shed, from Friday afternoon to Monday morning. 1. On Monday morning a chalked message was found on the inside of the shed door: “the middle shelf will not hold these boxes”. 2. The shed was locked from Friday evening until Monday morning; the only key was in the grower's pocket throughout, and the shed has no window and no other way in. 3. The boxes were unloaded from a van and carried into the shed on Friday afternoon. 4. Tomas helped that afternoon but left at two o'clock, before the van was opened and before anyone saw how heavy the boxes were. 5. Wren spent the afternoon in the van park and never came within twenty metres of the shed. 6. The grower says he did not write it and had no reason to leave a note for himself. - A. The grower wrote it himself; a denial is a claim, not a constraint. - B. Tomas wrote it before he left at two o'clock. - C. Wren wrote it while the boxes were being unloaded. - D. Someone got into the shed over the weekend. Your answer: ______ Authored hints ============== Only hints supplied by the puzzle authors are included. Items without a source hint are listed as missing; no hint text is generated or inferred. 0 worksheet items do not have an authored hint. No hint text was generated for them. puz-lateral-thinking-01 One short noun here has more than one everyday sense. Ask what a hot drink leaves behind on bare wood. puz-lateral-thinking-02 Nothing in the account says how long the doorstep errand took. puz-lateral-thinking-03 Count the posts, then count the people. puz-lateral-thinking-04 The librarian asked for a property, not for a book. Which property, and what job in this room needs it? puz-lateral-thinking-05 How many people can live behind one front door? puz-lateral-thinking-06 The distance is fixed and the effort is equal, so something else must differ. Watch what the stick does. puz-lateral-thinking-07 Nothing human repeats the same words at the same minute every single evening. puz-lateral-thinking-08 Where exactly is each printed label stuck? puz-lateral-thinking-09 Look hard at the little word joining Rosa's three events. puz-lateral-thinking-10 The guide can reach out and touch the summit. puz-lateral-thinking-11 Ask what each of the two counts is actually counting. puz-lateral-thinking-12 Every morning the switch is still off. Which explanation can light a bulb without moving that switch? puz-lateral-thinking-13 Ask what else in this building follows a weekly rhythm, then ask what that does to paper. puz-lateral-thinking-14 The crate must fit inside the car, but nothing says it must lie along a wall of it. puz-lateral-thinking-15 The missing message is itself a fact. What state of the world would produce it? puz-lateral-thinking-16 Four plants had exactly the same feed and were fine. What did the other four have that they did not? puz-lateral-thinking-17 Look at what the lost items actually are. puz-lateral-thinking-18 Work out how the conclusion is reached, then remove facts one at a time and see whether a rival suspect returns. puz-lateral-thinking-19 Somebody handed out eighteen of something, and not all of them went to children. puz-lateral-thinking-20 The first idea the wet floor suggests is closed off by the weather. What else in this corridor has moved? puz-lateral-thinking-21 Some of these facts make the theft stranger; exactly one makes it possible. Ask what the lock is actually holding. puz-lateral-thinking-22 Work out the earliest moment anybody could have known which chair the bag was on. puz-lateral-thinking-23 Treat the second remark as two filters: what was already decisive before the first remark, and what became decisive only because of it. puz-lateral-thinking-24 Look closely at what the postmaster actually observed, and at the gaps between those three moments. puz-lateral-thinking-25 Split the candidates twice over: who could get inside, and who could know how heavy the boxes were. Answer key ========== ! The answer key and worked explanations in this file belong only to this public, untimed educational practice source. No active aptitude suite or Novus Reasoning Challenge answer key is ever included in any download. Lateral thinking: open practice pack answer key Item Choice Answer ----------------------- ------ --------------------------------------------------------------------------------------- puz-lateral-thinking-01 C A pale circular mark left on the varnish by his mug. puz-lateral-thinking-02 A The errand at the door lasted hours, so the tea had ample time to cool. puz-lateral-thinking-03 D One person holds both posts, so the handover happened in one pair of hands. puz-lateral-thinking-04 B To hold the self-closing door open while the boxes are carried through. puz-lateral-thinking-05 A Flat four is home to two people, so there are two new neighbours. puz-lateral-thinking-06 C He rowed against the current going out and with it coming back. puz-lateral-thinking-07 B A timed recorded announcement played through the new ceiling speakers. puz-lateral-thinking-08 D The labels are on the lids, and the lids went back onto different tins. puz-lateral-thinking-09 A Rosa listed three things that happened without claiming that order. puz-lateral-thinking-10 C A scale model of the valley laid out in the grounds. puz-lateral-thinking-11 B Two of the doors serve the bin store and the shared stairwell, not homes. puz-lateral-thinking-12 D Mice moving about under the door trigger the motion-sensing bulb. puz-lateral-thinking-13 A The paper takes up damp over the cold weekend and feeds badly until the room warms. puz-lateral-thinking-14 B It stood corner to corner in the lift, whose floor diagonal is nearly three metres. puz-lateral-thinking-15 C On Monday evening the surgery held no Tuesday appointment in her name. puz-lateral-thinking-16 D The greenhouse overheating while its vent was jammed shut. puz-lateral-thinking-17 B Both totals rise when more people swim, so the swimmer count drives each. puz-lateral-thinking-18 A Salim's badge record for Wednesday morning. puz-lateral-thinking-19 C There are eighteen passengers for sixteen passenger seats. puz-lateral-thinking-20 D A water cooler spilt as it was moved out, and the through-draught scattered the papers. puz-lateral-thinking-21 A The rear wheel is held on by a lever that opens by hand. puz-lateral-thinking-22 D She saw the bag on that chair herself, between half past five and quarter to six. puz-lateral-thinking-23 C Six rows. puz-lateral-thinking-24 B That checks at three moments show where the key was in between. puz-lateral-thinking-25 A The grower wrote it himself; a denial is a claim, not a constraint. Worked explanations =================== puz-lateral-thinking-01 The method is sense-splitting: when a scene reads as impossible, find the one word carrying the weight and list its ordinary senses. Here the word can mean jewellery, a phone call or a circular mark, and only the last one fits bare varnish, a hot mug used without a mat, and a housemate who has lost nothing. Reading it as jewellery forces you to invent a lost item the facts rule out, and the phone reading dies on an empty call list. Next time a short common noun sits at the centre of a puzzle, try its second sense before you doubt the facts. puz-lateral-thinking-02 This is a narration gap. Two events written side by side feel adjacent in time, but nothing in the account says how long the middle lasted. Strip the story to what is stated: a fresh cup was poured, a door was answered, the tea was cold. The only unstated quantity is the length of the errand, and waiting with a neighbour for an engineer is exactly the kind of errand that runs for hours. Blaming the heating or the pot means contradicting a stated fact, which is always a worse move than filling in an unstated one. puz-lateral-thinking-03 The technique is role-counting. Six posts and five people means somebody wears two hats, so a treasurer passing accounts to a librarian can be one person moving a ledger from one pile to another. Two named roles never entail two bodies. The tempting route is to doubt the record, but the minutes are stated to be accurate and complete, so any story needing them to be wrong is beaten before it starts, and a paper ledger with no computer in the room closes off the electronic route. Whenever a record describes a transfer nobody saw, check whether both roles could belong to one person. puz-lateral-thinking-04 This is function-shifting: ask what an object can do, not what it is for. The volunteer's problem is a door that swings shut while both hands are full, and fixing anything to the door has been ruled out. Mass is the property being requested, and the only job in the scene that needs mass is holding a door. Weighing paper down is the right kind of idea but answers a problem nobody has, since there is no draught and the windows are shut. When a request names an odd property (heaviest, longest, coldest), let the property tell you the job. puz-lateral-thinking-05 The assumption is a quiet singular. One flat coming free feels like one person arriving, but a flat holds a household, and the text never commits to a number. Both entries name flat four, both are accurate, and nobody moved in or out midweek, so the only reading that keeps every fact is two people sharing one home. A rapid change of tenant contradicts the stated fact that nobody moved, and calling Dana forgetful contradicts the entries being accurate. Whenever a puzzle turns on “the” new person, check whether the text ever said there was only one. puz-lateral-thinking-06 This is the two-way trip test: equal effort over an equal distance should take equal time, so an unequal time means the medium itself is moving. The drifting stick shows water running away from the weir, which makes the outward leg an upstream leg and the return a downstream one. Tiredness and a short cut both need a stated fact to be false, since the effort was equal and the two points are fixed two kilometres apart, and still air rules out any wind. When the times differ and the route does not, look for something moving underneath. puz-lateral-thinking-07 The assumption is that a voice implies a speaker present. Three stated facts break it: the same six words, the same minute every evening, and an empty building. Human speech does not repeat to the second, but a recording does, and ceiling speakers were fitted last month. A colleague upstairs contradicts her being alone, an echo needs her to have spoken first, and a radio would never deliver identical words at an identical time. When a repeated event is exact rather than merely similar, look for a machine before you look for a person. puz-lateral-thinking-08 Track the label, not the tin. The labels live on the lids, and lids are interchangeable, so washing three tins and putting three lids back can shuffle every label without anyone touching one. The helper checked contents against labels as he filled, which rules out a filling error; the sacks are open and visible, which rules out a mislabelled sack; and doubting the cook's eyes contradicts a stated observation. When a container disagrees with its label, first ask which part of the container the label is attached to. puz-lateral-thinking-09 The technique is separating a list from a timeline. Rosa's sentence joins her three events with “and”, not “then”, so it commits her to three things happening, not to the order they happened in. The photograph fixes the real order: Theo was already there while the cake was whole. Inventing a second cake or a second gathering contradicts stated facts, and calling Rosa mistaken contradicts her account being truthful. Where a witness's sequence seems to clash with hard evidence, check whether a sequence was ever claimed. puz-lateral-thinking-10 This is a scale check. Four seconds between two points a walker would need an hour to cross only works if the points themselves are small. Three facts pin it down: the summit is within arm's reach, the whole valley is in view without a turn of the head, and nothing printed or on a screen is involved. That triangle describes a model laid out on the ground. A high viewpoint gives the view but never the touch, and a cable car would still take minutes. When a distance behaves oddly, question the size of the thing before the speed of the traveller. puz-lateral-thinking-11 The move is to check what each side is counting. One count is of doors and the other is of tenancies, and a block contains doors that open onto a bin store and a stairwell as well as doors that open into homes, so the two totals were never counting the same objects. Every rival story needs a stated fact to fail: no flat is empty, no tenant holds two, and the file is complete. When two honest counts of “the same thing” disagree, write down what each one actually counts before you go looking for a mistake. puz-lateral-thinking-12 This is elimination between rival stories, judged against every fact rather than the most vivid one. A person getting in needs a key, and the only other keyholder has been abroad for three weeks. The shed lighting itself needs a mechanism, and the switch is found off each morning while the light is on, which kills the sticking-switch idea and points at the one part that can act on its own: a sensing bulb with mice moving beneath the door. A painted window that does not open ends the borrowed-light story. A surviving explanation must fit all the facts, not most of them. puz-lateral-thinking-13 The decisive detail is the one that reads as scenery: the building is unheated at weekends. Paper in an open rack against an outside wall takes up damp over two cold days, swells at the edges and misfeeds, then dries as the room warms, which is exactly why the trouble clears by lunchtime. Volume and paper stock are stated to be identical all week, so neither a heavy morning nor a wrong ream can be the difference, and the engineer found nothing to blame. When a fault keeps to a timetable, look for something else on the same timetable. puz-lateral-thinking-14 This is a frame change rather than an object change. The crate is longer than any single side of the lift, but a box is not limited to its sides: the diagonal of a two-metre square floor is about 2.8 metres, comfortably more than 2.05. Nothing about the crate needs to change, only its angle. The stairs are stated to take nothing over 1.6 metres at any angle, so tilting there buys nothing, and dismantling contradicts the crate arriving unopened. When something will not fit, measure the longest line of the space rather than its width. puz-lateral-thinking-15 This is reasoning from an absent negative: an event that always happens becomes evidence when it does not happen. The surgery texts every patient the evening before, her phone keeps everything and was receiving other messages that Monday evening, so the silence is real information rather than a gap in the record. Claim only what it licenses, though: it fixes the state of the booking system at the moment the texts went out, not the whole history. A Tuesday-morning cancellation would still have produced Monday's message, which is why that story does not fit. Absence proves something narrow; resist widening it. puz-lateral-thinking-16 The method is the controlled comparison. All eight plants had the same feed at the stated strength, and the four outdoors were fine, so the feed cannot be what separates the healthy from the harmed. The vent jamming on the last day of May and being freed on the eleventh of June brackets the damage almost exactly, and a sealed greenhouse cooks in early summer. Soil worn out over nine years would not act within ten days, and inventing a glass-only disease adds a fact the scene never supplied. When two candidates share a timing, prefer the one that also matches the split between what was harmed and what was not. puz-lateral-thinking-17 This is a common cause, not a chain. Takings and lost property both climb on gala and lesson days, and what gets handed in is towels, goggles and caps: swimming kit, not cafe kit. So the number of swimmers moves both totals and neither total acts on the other. Careless customers would leave cups and coats behind; a story about busy staff predicts fewer items reaching the desk, not more. Whenever two counts move together, look for the third quantity moving them both before you draw an arrow between them. puz-lateral-thinking-18 Test necessity by deletion: take one fact away and ask whether more than one story still survives. This conclusion is reached by elimination. The access list closes the field to four people, and the train, the wrist and the badge time remove three of them. Delete any of those and a second suspect walks straight back in. Positive evidence that the survivor was present adds nothing, because elimination has already left him alone. That is the general shape: an argument from elimination needs its frame and its exclusions, never a confirmation of the one left standing. puz-lateral-thinking-19 The count you need is never stated, but it is forced. Eighteen lunches went out with none spare and two of them went to the adult helpers, so sixteen children are on the trip. Now add the helpers back, because helpers occupy seats: eighteen people want a passenger seat and the licence allows sixteen. Two slips are common here: treating all eighteen lunches as children, and stopping at the sixteen children as though the adults travelled by magic. When a total is missing, look for a quantity that was handed out one to one. puz-lateral-thinking-20 Two-stage inference: form the natural first guess, kill it, then rebuild from what is left. Water by an open door says rain, but nine dry days and dry ground outside close that route. What remains is already on the page: a heavy water cooler dragged out through the propped door, and a window wedged open at the far end, so opening the fire door creates a through-draught the moment it is propped. A ceiling leak explains the water but not the paper; a hurried search explains the paper but not the water. Prefer the story that covers every symptom rather than the loudest one. puz-lateral-thinking-21 Separate the facts that enable from the facts that merely exclude. No cut marks and an untouched key close off routes; the lock still hanging shut on the rail restates the mystery rather than resolving it. Only one fact opens a door: the part sitting inside the lock comes off by hand, so the rest of the bicycle could be lifted away from its own lock in seconds. That also names the real error. The lock was securing a detachable component rather than the frame. When something apparently impossible has happened, list which facts could have made it possible, not which ones make it stranger. puz-lateral-thinking-22 Build a knowledge timeline. The note names a particular chair in a cafe Yusuf had never used before, so its writer knew something that only came into existence at half past five. He told nobody, the flat has no telephone and her mobile was off, and she left at quarter to six and has not returned, so the knowledge had to be picked up in person inside that fifteen-minute window. A note written later contradicts her leaving time, and a lucky guess is closed off by his never having been to the place. Ask what each person could have known, and the exact moment they could have known it. puz-lateral-thinking-23 Work knowledge claims as filters, one at a time. Twelve splits as 2×6, 3×4, 4×3, 6×2 and eighteen as 2×9, 3×6, 6×3, 9×2. A row count that fixes the total would have told Petra the answer, so her ignorance leaves rows of two, three or six. Treat the reply as two separate filters: “I could not before” removes per-row counts of four and nine, which were decisive on their own, and “now I can” removes six, since two rows of six and three rows of six both survive. What is left is two chairs a row giving twelve, or three a row giving eighteen, and both of those layouts have the same number of rows. puz-lateral-thinking-24 The faulty step is treating spot checks as continuous observation. Three sightings at half past nine, one o'clock and six o'clock sit happily alongside the key being out from ten to nine until twenty past, and out again from twenty-five to ten in the evening. Precisely the windows the book records, and precisely the moments the doors were worked. Nothing else has to give: the sightings can all be accurate, the book can be honest, and the lock untouched. When a witness says something never happened, ask what they actually watched and for how long, then check whether the unwatched gaps are large enough to hold the event. puz-lateral-thinking-25 Two constraints do the work here, one physical and one about knowledge. Nobody could enter the locked shed over the weekend, and the message names those boxes, so it was chalked inside before Friday evening. Tomas left before the van was even opened, so he could not have known the weight; Wren never came near the shed, so she could not have written on its inner face. That leaves one person, and his denial is testimony rather than a constraint: it rules nothing out. Sort your facts into what a person could do and what a person could know, and keep bare say-so out of both lists. Source: https://learn.novusstreamsolutions.com/puzzles/lateral-thinking