If I give you seven apples, you will then have five times as many as I would then have.

However, if you give me seven apples, we will then both have the same number of apples.

How many apples do I currently have?

Puzzle Copyright © Kevin Stone

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Hint

A little bit of algebra might help.

Answer

I have 14 apples and you have 28 apples.

Reasoning

We can work this out with a little algebra. I have A apples and you have B apples, then

[1] 5 x (A - 7) = B + 7

[2] A + 7 = B - 7

From [1] we have:

5A - 35 = B + 7

[3] 5A = B + 42

From [2] we have:

[4] A + 14 = B

We can then use [4] in [3] to give:

5A = (A + 14) + 42

5A = A + 56

4A = 56

A = 14

Which gives B = 28 (by [4]).