Question

A pile of sand has a weight of 65 kg.

Some of the sand is put into a small sack.
The rest of the sand is put into a large sack.
The sand in the large sack weighs 15 kg more than the sand in the small sack.
What is the weight of the sand in the small sack?

Answer 1

25 kg

Explanation:

The sum of the weights of the small and large sacks is 65 kg. The larger sack weighs 15 kg more. You want the weight of the smaller sack.

Setup

Let w represent the weight of the sand in the small sack. Then (w+15) is the weight of the sand in the larger sack. The total weight is 65 kg, so we have ...

w +(w+15) = 65

Solution

Subtracting 15 from both sides gives ...

2w = 50

w = 25

The weight of the sand in the small sack is 25 kg.