Twelve equal pieces of cake from four cuts
A round cake, uniform in height, must be divided into twelve pieces of equal size using four straight cuts. Pieces may not be moved between cuts.
How do you do it? Then explain why three vertical cuts through the centre can never produce twelve pieces, and what the maximum number of pieces from four cuts would be if the pieces did not have to be equal.
Show a hint
Not every cut has to be vertical.
Your answer
Solving needs a free account
Answers, streaks and solutions unlock when you are signed in. Reading the question and the hint stays free.
Discussion
Sign in to join the discussion · reading is open to everyone
💡 Discussion rules
- No full solutions here. Hints and approaches only.
- Complexity, edge cases and intuition are the point.
- Interview experiences are welcome. Respect your NDAs.
Loading discussion…
Learn the concepts
The theory behind this question.
Related questions
The bookworm and the ten volumesCutting a 4 by 4 by 4 cube when you may restackHalf a jug with no markingsCrossing the moat with two short planksNine dots, four straight lines
All questions →