How much water must be added to 52 litres of milk at 1 1⁄2 litres for 20 so as to have a mixture worth 10 2⁄3 a litre? Select:
A) 10 litres	B) 13 litres	C) 15 litres	D) 18 litres	E) none of these

Rationale: c . p . of 1 litre of milk = ( 20 × 2 ⁄ 3 ) = 40 ⁄ 3 ∴ ratio of water and milk = 8 ⁄ 3 : 32 ⁄ 3 = 8 : 32 = 1 : 4 ∴ quantity of water to be added to 52 litres of milk = ( 1 ⁄ 4 × 52 ) litres = 13 litres . answer b
Answer: B