how many liters of water must be added to 20 liters of milk and water containing 10 % water to make it 60 % water ?
"by rule of alligation : 60 % - 10 % = 50 % 100 % - 60 % = 40 % quantity of pure water : quantity of the mixture = 5 : 4 there are 20 liters of mixture , so we need to add 25 liters of pure water . the answer is e ."
multiply(divide(20, 10), divide(60, 10))