IBPS Clerk Prelims Model Paper 8

Two metals X and Y are to be used for making two different alloys. If the ratio by weight of X : Y in the first alloy is 6 : 5 and that in the second alloy is 7 : 13, how many kilograms of X metal must be melted along with 11 kg of the first alloy and 20 kg of the second, so as to produce a new alloy containing 40% of metal Y?