Question

40 litres of milk contain 10% water find the quantity of water to be added to the milk so that it may contain 20% water

Answer 1

in 40 litre the quantity of water is 4 litre and milk is 36 litre which is equal to 90% when the water becomes 20 % then it will be 80% so
80%=36 then 100%= (36/80)×100 =45 litre in 45 litre milk is 36 litre so quantity of water is 45-36 =9 litre extra value is 5 litre