Subject: mathqa
Question: a money lender lent rs . 1000 at 4 % per year and rs . 1400 at 5 % per year . the amount should be returned to him when the total interest comes to rs . 350 . find the number of years .
Option: 
A: 3.2
B: 4
C: 3.75
D: 4.25
Answer: A