Question

A certain mixture of acid and water contains 20% acid.when 15 liters of water are added to this mixture,the concentration of acid reduces to 16% what is the amount of the original mixture(liters)​

Answer 1

Mixture of acid and water = 25 litre

If 20% is acid then 80% must be the water

25*20% = 5ltr acid

25*80% = 20ltr water

To make the acid 10%, water should be 90%

25 ltr * 10% = 2.5ltr acid

25 ltr* 90% =22.5ltr water

Add both for mixture = 2.5l acid +22.5l water = 25