Hard Brainteasers Interview Questions
These are the brainteasers questions that separate candidates who know the technique from those who can apply it under pressure.
40 questions, 27 of them free to practise right now.
- A Fibonacci power sumHardBrainteasersView →
- A coin thick enough to land on its sideHardProbabilityBrainteasersView →
- A flea's shortest escape across a boxHardBrainteasersCalculusView →
- A geometric series that sums to a squareHardBrainteasersView →
- A triangle of consecutive integersHardBrainteasersView →
- A weighted sum of binomialsHardCombinatoricsBrainteasersView →
- Average of near-diagonal numbersHardCombinatoricsBrainteasersView →
- Cats and miceHardBrainteasersView →
- Cubes over the terminating denominatorsHardBrainteasersCalculusView →
- Digits with distinct pairwise sumsHardCombinatoricsBrainteasersView →
- Doors toggled by primesHardCombinatoricsBrainteasersView →
- Largest pairwise-coprime subset sumHardCombinatoricsBrainteasersView →
- Locks for a four-of-seven safeHardCombinatoricsBrainteasersView →
- Measuring two pintsHardBrainteasersView →
- Pairing with a difference of 1 or 11HardCombinatoricsBrainteasersView →
- Rotations divisible by 37HardCombinatoricsBrainteasersView →
- Shuffles to restore the deckHardCombinatoricsBrainteasersView →
- Smallest number with digit product 10000HardCombinatoricsBrainteasersView →
- Sum of repeating decimalsHardCombinatoricsBrainteasersView →
- Sums of fours and fivesHardCombinatoricsBrainteasersView →
- The number with no new digitsHardBrainteasersView →
- The survivor in the circleHardBrainteasersView →
- Three eggs, nine dropsHardCombinatoricsBrainteasersView →
- Triangle with equal side sumsHardCombinatoricsBrainteasersView →
- Twelve balls, one oddHardBrainteasersView →
- Weighings for the odd beanHardBrainteasersView →
- When k-to-the-k is a squareHardCombinatoricsBrainteasersView →
- Ages from product and sumHardCombinatoricsBrainteasers Premium
- Bertrand's chordHardProbabilityBrainteasers Premium
- Blue-eyed islandersHardBrainteasers Premium
- Defective stack of coinsHardCombinatoricsBrainteasers Premium
- Handshakes at a dinner partyHardCombinatoricsBrainteasers Premium
- Hats in a lineHardBrainteasers Premium
- Hats with 100 colorsHardBrainteasers Premium
- Last one standingHardCombinatoricsBrainteasers Premium
- Prisoners and the boxesHardProbabilityBrainteasers Premium
- Prisoners and the light switchHardBrainteasers Premium
- The racing camelsHardBrainteasers Premium
- Triangle that swallows the centerHardProbabilityBrainteasers Premium
- Two eggs, 100 floorsHardBrainteasers Premium
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