Flatbread Pan
Read the puzzle
Three flatbreads, labelled A, B and C, each have two sides marked 1 and 2. A pan holds 2 flatbreads at a time, and each side needs 1 minute to cook. What is the fewest number of minutes needed to cook all 3 flatbreads on both sides?
A pan holds 2 flatbreads. Each side needs 1 minute. How few minutes can it take to cook 3 flatbreads on both sides?
Do not wait for one flatbread to finish before starting the third.
3 minutes
Minute 1: A and B. Minute 2: A's other side and C. Minute 3: the other sides of B and C.
How to solve it
Count the work first. Three flatbreads with two sides each make 3 × 2 = 6 sides to cook. The pan cooks 2 sides per minute, so no plan can beat 6 ÷ 2 = 3 minutes. The question is whether the pan can be kept full every minute.
Minute 1: cook side 1 of A and side 1 of B.
Minute 2: flip A to cook its side 2, and take B off to make room for side 1 of C. A is now done.
Minute 3: cook side 2 of B and side 2 of C. Both are now done.
All 6 sides are cooked in 3 minutes, and the pan was full the whole time.
The usual wrong answer is 4 minutes: finish A and B together in 2 minutes, then cook C alone for 2 more. In those last two minutes half the pan sits empty, which wastes two side-slots. The fix is to start C before B is finished.
Takeaway: when a container has room for two, find the total work, divide by the capacity, then arrange the steps so no slot is ever left empty.
