Solutions
Given:
Vessel contains 10 L mixture out of which 10% is water
Calculations:
Volume of the mixture is 10 liters, in which the quantity of water is 10%
⇒ 10 × (10/100) = 1 liters
We need 25% water in the mixture.
Here suppose you mix x litres water in 10 litre mixture.
Then the quantity of water = 1 + x litres
And the quantity of mixture = 10 + x litres.
We need 25% of water. So,
⇒ [(1 + x)/10 + x] × 100 = 25
⇒ (1 + x)/10 + x = 25/100
⇒ (1 + x)/10 + x = 1/4
⇒ 4 + 4x = 10 + x
⇒ 4x – x = 10 – 4
⇒ 3x = 6
⇒ x = 6/3
⇒ x = 2
∴ We should add 2 litres of water.