Question

Sid has 2 boxes of markers with the same number of markers in each box. He gives 3 markers to his sister. Now Sid has 13 markers. How many markers were in each box?

Answer 1

Answer:  8

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Explanation:

If he gave 3 markers, and it means he has 13 markers left, that must mean he started with 13+3 = 16 markers overall. Divide that count among the two boxes to get 16/2 = 8 markers per box.

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Using algebra, we can say,

x = number of markers per box

2x = number of markers total before he gives his sister any markers

2x-3 = number he has after giving the 3 markers

2x-3 = 13

2x = 13+3

2x = 16

x = 16/2

x = 8