Written by Kerry Dent

Difficulty: Tricky

On the expedition’s small BBQ, only two potato cakes will fit at the same time. If it takes five minutes to cook one side of a potato cake and five minutes to cook the other side, what will be the minimum time required to cook three potato cakes on the BBQ?

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Brainteaser answer

The minimum time required will be 15 minutes. Cook potato cakes A and B for five minutes. After five minutes turn A over, remove B and replace it with C and cook for five minutes. After 10 minutes, remove A, because it’s fully cooked; turn C and put B back on and cook for a further five minutes. After 15 minutes have elapsed, all three potato cakes are cooked.

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2 responses

  1. Damien Avatar

    How do I solve this for each additional potato cake that I cook?

    1. David Avatar

      It’s not too hard work out the best way to cook even numbers of cakes – split them into pairs and cook them off.

      For most odd numbers, you can cook three cakes, and you’ll have an even number left.

      Then you can use the even procedure to cook them.

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