Puzzle LanternThese eight logic puzzles each have one answer under the stated rules. They cover matching, ordering, truth conditions, numerical constraints and elimination. Try a deduction, open the hint if needed, then check the reasoning. No outside knowledge or hidden wordplay is required.
All examples are original to this article. Use only the listed possibilities. “Different” means no two items share the same assignment, and positions in a row run from left to right.
1. Three drinks
Ada, Ben and Cy each have one different drink: tea, coffee or cocoa. Ada has neither tea nor coffee. Ben does not have coffee. Who has each drink?
Show hint for the drinks
Start with the person who has two exclusions.
Reveal answer and explanation
- Ada cannot have tea or coffee, so Ada has cocoa.
- Ben can now have only tea or coffee. Coffee is excluded, so Ben has tea.
- Cy has the remaining drink, coffee.
Ada: cocoa. Ben: tea. Cy: coffee. Every choice is forced.
2. Order the saplings
Four pots stand in one row, each containing one sapling: birch, cedar, elm or fir. Cedar is immediately to the right of birch. Elm is somewhere left of birch. Fir is somewhere right of cedar. What is the order?
Show hint for the saplings
Treat birch and cedar as one adjacent pair.
Reveal answer and explanation
- The birch-cedar pair needs space on both sides: elm on its left and fir on its right.
- In four positions, the pair must therefore occupy positions 2 and 3.
- Elm fills position 1 and fir position 4.
Elm, birch, cedar, fir. Putting the pair at either end would leave no space for one required neighbour.
3. One truthful label
A key is in exactly one of three boxes, A, B or C. Exactly one of these labels is true: A says “The key is in B.” B says “The key is not in B.” C says “The key is not in A.” Which box holds the key? Labels need not describe their own boxes.
Show hint for the labels
Compare the statements on A and B before trying each box.
Reveal answer and explanation
- A’s and B’s statements are exact opposites, so precisely one of them must be true.
- That already uses the one permitted true statement. C’s statement must be false.
- “The key is not in A” being false means the key is in A.
Box A. Checking: A’s label is false, B’s is true and C’s is false.
4. A three-digit code
A code uses the digits 1, 2 and 3 exactly once each. Its second digit is greater than its first. Its third digit is less than its first. What is the code?
Show hint for the code
The first digit needs both a smaller and a larger neighbour in the available set.
Reveal answer and explanation
- The first digit cannot be 1, because no available digit is smaller.
- It cannot be 3, because no available digit is larger.
- It is therefore 2. The larger second digit must be 3 and the smaller third digit must be 1.
231. Each digit is used once, and both comparisons hold.
5. A route around a closure
A directed path has exactly these connections: A→B, A→C, B→D, C→D, C→E, D→F and E→F. You may travel only in the arrow direction. Point D is closed and cannot be entered. Find the route from A to F.
Show hint for the route
Remove every connection that uses D.
Reveal answer and explanation
- From A, choosing B leads only to D, which is closed.
- You must choose C. From C, the connection to D is also unavailable, leaving E.
- From E, go directly to F.
A→C→E→F. These are all permitted connections; there is no other route once D is excluded.
6. Choose a three-person team
Choose exactly three people from Asha, Bo, Chen, Dev and Eli. Asha must be included. Eli is unavailable. Bo and Chen cannot both be selected. Dev can be selected only if Bo is also selected. Who is on the team?
Show hint for the team
After including Asha and excluding Eli, consider each pair from the other three people.
Reveal answer and explanation
- Two places remain for Bo, Chen and Dev.
- Bo plus Chen breaks the rule against choosing both.
- Chen plus Dev leaves Dev without Bo, so that pair also fails.
- Bo plus Dev satisfies both rules.
Asha, Bo and Dev. The three possible pairs have all been considered.
7. Fill four cells
Put 1, 2, 3 and 4 into a 2×2 grid, using each exactly once. The top row totals 7. The left column totals 4. The bottom-right cell is even. Find the arrangement.
Show hint for the four cells
Which two available numbers can total 7?
Reveal answer and explanation
- The top row must contain 3 and 4.
- If top-left were 4, bottom-left would need to be 0 to total 4. Zero is not available.
- Top-left is therefore 3, top-right 4 and bottom-left 1.
- The remaining 2 fills bottom-right and is even, as required.
Top row: 3, 4. Bottom row: 1, 2.
8. Complete a Sudoku row
In standard 9×9 Sudoku, each row, column and 3×3 box contains digits 1–9 exactly once. This deliberately almost-complete grid has one blank, marked “?”. Find it by elimination.
| 1 | 2 | 3 | 4 | ? | 6 | 7 | 8 | 9 |
| 4 | 5 | 6 | 7 | 8 | 9 | 1 | 2 | 3 |
| 7 | 8 | 9 | 1 | 2 | 3 | 4 | 5 | 6 |
| 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 1 |
| 5 | 6 | 7 | 8 | 9 | 1 | 2 | 3 | 4 |
| 8 | 9 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
| 3 | 4 | 5 | 6 | 7 | 8 | 9 | 1 | 2 |
| 6 | 7 | 8 | 9 | 1 | 2 | 3 | 4 | 5 |
| 9 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
Show hint for the Sudoku
Compare the first row with the complete set 1–9.
Reveal answer and explanation
- Row 1 already has 1, 2, 3, 4, 6, 7, 8 and 9.
- The only missing digit is 5, so row 1 column 5 must be 5.
- Column 5 and the top-middle 3×3 box also each lack 5, so this placement satisfies all three constraints.
5. A fuller puzzle repeats this kind of constraint checking across many cells. Puzzle Lantern’s Sudoku uses the standard 9×9 format, with a Daily grid and additional More puzzles rounds.
When a deduction stalls
Write down the remaining possibilities and look for the strongest restriction. If two arrangements still fit every rule, you have not yet proved one answer. Checking alternatives is part of solving, not a failure to see a trick.
Make room for a daily puzzle
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Puzzle Lantern is made for entertainment. It is a collection of games, and nothing more is claimed for it.