Subject: mathqa
Question: a person spends 40 % of his salary on food , 25 % on house rent , 15 % on entertainment and 10 % on conveyance . if his savings at the end of the month is rs . 1200 , then his salary per month in rupees is :
Option: 
A: 10000
B: 6000
C: 12000
D: none of these
Answer: C