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]).
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