Who sits where, drinking what?
Difficulty: moderate. One ordering clue and one position clue combine to unlock everything.
Ines, Kofi and Lena sit in a row of three seats — left, middle and right, as seen from the front. Each drinks one of tea, coffee or water.
One person per seat, one drink per person, each drink used once. "Immediately to the right" means the next seat to the right.
- Kofi sits immediately to the right of the tea drinker.
- Lena is not in the middle seat.
- The coffee drinker sits on the far left.
- Ines does not drink water.
Reveal the ordered elimination steps
- Clue 1: the tea drinker has someone to their right, so tea is not on the right. Kofi has someone to his left, so Kofi is not on the left.
- Clue 3: coffee is on the left, so tea is not on the left. Tea must be in the middle.
- Back to clue 1: Kofi sits immediately right of the middle seat, so Kofi is on the right.
- Clue 2: Lena is not in the middle, and the right is taken, so Lena is on the left. Ines takes the middle.
- Drinks by seat: Lena (left) has coffee, Ines (middle) has tea, so Kofi has water.
- Check clue 4: Ines drinks tea, not water. The answer is consistent with every clue.
| Seat | Person | Drink |
|---|---|---|
| Left | Lena | Coffee |
| Middle | Ines | Tea |
| Right | Kofi | Water |
Clue 4 turns out to be a confirmation rather than a key. Setters sometimes include such clues; noticing that a clue was not needed is a good sign your chain of reasoning was tight.
The logic grid, explained
Logic grid puzzles became famous through the so-called Zebra Puzzle, published in Life International in 1962 and often, without evidence, attributed to Albert Einstein. Its five houses and many clues are a long workout, but the method is identical to our three-seat challenge. Arthur Conan Doyle gave the approach its best-known motto in The Sign of the Four (1890): eliminate the impossible, and whatever remains must be the truth.
Build the grid
Draw a table for each pair of categories: people against seats, people against drinks, seats against drinks. Every cell represents one possible pairing. A cross means "impossible"; a circle means "certain".
Mark direct clues first
Clues like "Lena is not in the middle" fill a single cross immediately. Do these before tackling relational clues; they shrink the problem with no risk.
Cascade every circle
When you place a circle, cross out every other cell in its row and column within that table. Then copy the information to the other tables. Forgetting to cascade is the single most common reason people feel stuck when the answer is already within reach.
Handle ordering clues carefully
"Immediately to the right of" tells you two things: the person on the left cannot be at the right end, and the person on the right cannot be at the left end. Write both consequences down before combining the clue with anything else, exactly as in step 1 above.
Every cross is a small, permanent win. Collect enough of them and the answer has nowhere left to hide.
When you seem to be stuck
Re-read each clue and ask what it forbids rather than what it suggests. Check whether any row has only one empty cell. Look for two clues that mention the same person or thing; combined clues often reveal what neither shows alone. As a last resort, try a careful "what if": assume one option, follow it until it either works or contradicts a clue, and if it contradicts, cross that option out. That is still deduction, as long as you test fully rather than stopping at the first comfortable result.
Raymond Smullyan's puzzle books and Martin Gardner's long-running "Mathematical Games" column in Scientific American are excellent places to see how varied this kind of reasoning can be.