In 120 litres of mixture of milk and water, waterisonly 25%. The milkman sold 20 litres of this mixture and then he added 16.2 litres of pure milk and 3.8 litres of pure water in the remaining mixture. What is the percentage of water in the final mixture?

Water in 120 L rnixture $=120\times \frac{25}{100}=30 \mathrm{L}$

Milk in 120 L mixture $=120-30=90 \mathrm{L}$

$\therefore$ Ratio of Milk and Water= 90 : 30 = 3 : 1

Milk in 20 L mixture $=20\times \frac{3}{4}=15 \mathrm{L}$

$\therefore$ Water in 20 L mixture= 20-15 = 5 L 

Water in final mixture= 30- 5 + 3.8 = 28.8 L 

Total final mixture= 120-20 + 16.2 + 3.8 = 120 L 

Hence, percentage of Water in the final mixture

$=\frac{28.8}{120}\times 100=24\mathrm{\%}$