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, all free to practise.
- 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 →
- Ages from product and sumHardCombinatoricsBrainteasersView →
- Average of near-diagonal numbersHardCombinatoricsBrainteasersView →
- Bertrand's chordHardProbabilityBrainteasersView →
- Blue-eyed islandersHardBrainteasersView →
- Cats and miceHardBrainteasersView →
- Cubes over the terminating denominatorsHardBrainteasersCalculusView →
- Defective stack of coinsHardCombinatoricsBrainteasersView →
- Digits with distinct pairwise sumsHardCombinatoricsBrainteasersView →
- Doors toggled by primesHardCombinatoricsBrainteasersView →
- Handshakes at a dinner partyHardCombinatoricsBrainteasersView →
- Hats in a lineHardBrainteasersView →
- Hats with 100 colorsHardBrainteasersView →
- Largest pairwise-coprime subset sumHardCombinatoricsBrainteasersView →
- Last one standingHardCombinatoricsBrainteasersView →
- Locks for a four-of-seven safeHardCombinatoricsBrainteasersView →
- Measuring two pintsHardBrainteasersView →
- Pairing with a difference of 1 or 11HardCombinatoricsBrainteasersView →
- Prisoners and the boxesHardProbabilityBrainteasersView →
- Prisoners and the light switchHardBrainteasersView →
- 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 racing camelsHardBrainteasersView →
- The survivor in the circleHardBrainteasersView →
- Three eggs, nine dropsHardCombinatoricsBrainteasersView →
- Triangle that swallows the centerHardProbabilityBrainteasersView →
- Triangle with equal side sumsHardCombinatoricsBrainteasersView →
- Twelve balls, one oddHardBrainteasersView →
- Two eggs, 100 floorsHardBrainteasersView →
- Weighings for the odd beanHardBrainteasersView →
- When k-to-the-k is a squareHardCombinatoricsBrainteasersView →
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