Question

A milkman makes a profit of 20 by selling milk mixed with water at rs. 9 per litre. if the cost of 1 litre of pure milk is 10 what is the ratio of milk and water in the mixture

Answer 1

7:3 is the answer.if he take 'x' litre of milk and 'y' litre of water and mix them to sell it, then according to question our equation will be as shown in the above picture.solve the above equation by hit and trial to get the answer as 7:3