This is a CSIR-NET December 2016 Part A question of Mathematical Sciences, Chemical Sciences, Earth Sciences.

Question discussed: A milkman adds 10 litres of water to 90 litres of milk. After selling 1/5th of the total quantity, he adds water equal to the quantity he has sold. The proportion of water to milk he sells now would be

(1) 72: 28 (2) 28: 72 (3) 20: 80 (4) 30: 70

Discussed by – Christy Varghese