Question

A solution of water and salt contains 8% salt. when 25 litre of water is evaporated percentage of salt insolution becomes 12%. find initial quantity of mixture

Answer 1

Let the amount of solution be x.

Amount of salt = 0.08x

Amount of water = 0.92x

When 25 litres is evaporated :

New amount of water = 0.92x - 25...... 1)

The remaining amount of solution is :

= x - 25

The new amount of water is :

0.88(x - 25)

= 0.88x - 22.......... 2)

We equate 1 and 2 since they both represent the new volume of water.

0.88x - 22 = 0.92x - 25

0.92x - 0.88x = - 22 + 25

0.04x = 3

x = 3/0.04

x = 75 litres

The initial quantity of the mixture is thus :

= 75 litres