A milk vendor has 2 cans of milk. The first contains 25% water and the rest milk. The second contains 50% water. How much milk should he mix from each of the containers so as to get 12 litres of milk such that the ratio of water to milk is 3 : 5?

Question: A milk vendor has 2 cans of milk. The first contains 25% water and the rest milk. The second contains 50% water. How much milk should he mix from each of the containers so as to get 12 litres of milk such that the ratio of water to milk is 3 : 5?Solution:Let the cost of 1 litre milk be Tk. 1Milk in 1 litre mix. in 1st can = 3/4 litre, C.P. of 1 litre mix. in 1st can Tk. 3/4Milk in 1 litre mix. in 2nd can = 1/2 litre, C.P. of 1 litre mix. in 2nd can Tk. 1/2Milk in 1 litre of final mix. = 5/8 litre, Mean price = Tk. 5/8By the rule of alligation, we have:⇒ Quantity of 2nd can : Quantity of 1st can = (3/4 - 5/8) : (5/8 - 1/2) = (6 - 5)/8 : (5 - 4)/8 = 1/8 : 1/8 = 1 : 1∴ Quantity of mixure taken from each can = 12 × (1/2) = 6 litres