Question

in a mixture of milk and water of 40 litres water is 5%. the amount of water (in litres) to be added to this mixture so as to make water 10% is

Answer 1

From 40 litres the amount of water is :

5/100 × 40 = 2litres

So :

5% = 2

Let the amount of water to be added to make it 10% = x

We want the amount of water to increase by x and this = x + 2 litres

The total amount becomes 40 + x

In order to make 10%:

(x + 2) / (40 + x) × 100 = 10

100x + 200 / 40 + x = 10

100x + 200 = 10(40 + x)

100x + 200 = 400 + 10x

100x - 10x = 400 - 200

90x = 200

x = 200/90 = 20/9 litres