How to solve logic grid puzzles
Logic grids: the table does the thinking
Einstein-style puzzles are unsolvable in your head and mechanical on a grid. Every clue becomes ✓s and ✗s; every ✓ sprays new ✗s; repeat until forced.
Updated
Three people, three drinks, three pets, four clues — and the question of who drinks tea. Held in working memory, the clues melt into each other; laid on an elimination table they become a calculation. The skill being tested is disciplined bookkeeping, and it transfers to every constraint puzzle on any test.
Clues come in two kinds
Direct clues place or ban outright ('Ada has the tea', 'Ben does not have the cat') — harvest them first, they're free. Relational clues link one attribute to another ('the tea drinker keeps the dog') — they activate later, the moment one side of the link gets pinned.
Every ✓ sprays ✗s
Each person has exactly one drink, one pet, one everything. So the instant a ✓ lands, cross out its entire row and column in that block. Those ✗s are what trigger the next deduction — a row with two ✗s has its third cell forced. The cascade IS the solving.
Re-read the clue list each pass
A relational clue that said nothing on first reading becomes decisive after two placements. Loop the list until a full pass adds nothing — only then have the clues been spent.
The strategy
- Sketch the grid: people down the side, each attribute block across.
- Pass 1 — apply every direct clue.
- After every ✓, fill the forced ✗s immediately.
- Loop the relational clues; each pass converts more of them.
- Answer from the finished grid, not from memory of the clues.
Common traps
- A relational clue filed as a placement — 'the tea drinker keeps the dog' pins nobody until one side is placed.
- Negatives are information: 'not the tea drinker' plus two other ✗s is a placement.
- Stopping at the first consistent-looking fill — the grid must be forced, not merely possible.
- Skipping the ✗-spray after a ✓ — the deduction chain starves without it.
Speed · ~110s/item: Budget 90–150 seconds on full grids. The table feels slower than intuition for the first day and is then both faster and error-proof.
Try it yourself: 4 practice questions
Pick an answer, then reveal it. Nothing is recorded, there is no clock, and none of these questions is ever used in a test.
Each person has a different sport; each option is used exactly once. Ada has the karate sport. Elif has the golf sport. Which sport does Dev have?
Reveal the answer
The answer is B — chess.
Show why — the worked reasoning
Each person has a different color; each option is used exactly once. Ben has the violet color. Dev has the blue color. Which color does Elif have?
Reveal the answer
The answer is B — yellow.
Show why — the worked reasoning
Each person has a different drink; each option is used exactly once. Elif has the juice drink. Cleo has the tea drink. Which drink does Ben have?
Reveal the answer
The answer is B — water.
Show why — the worked reasoning
Each person has a different sport; each option is used exactly once. Ben has the chess sport. Ada has the golf sport. Which sport does Elif have?
Reveal the answer
The answer is B — rowing.
Show why — the worked reasoning
Try questions like this
The free test has 20 questions across abstract, numerical, verbal and spatial reasoning. It takes 12 minutes, needs no sign-up, and explains every answer.
A free account opens every lesson, practice drills and a study plan built from your results.
Questions people ask
Will logic grids questions be on the free test?
Maybe. The free test gives verbal & logic 5 of its 20 questions, spread across 11 different question types, so any one test may or may not include this kind.