Subject: mathqa
Question: how much water must be added to 60 litres of milk at 1 1 ⁄ 2 litres for 20 so as to have a mixture worth 10 2 ⁄ 3 a litre ?
Option: 
A: 12 litres
B: 18 litres
C: 15 litres
D: none of these
Answer: C