A money lender lent Rs. 1000 at 3% per year and Rs. 1400 at 5% per year. The amount should be returned to him when the total interest comes to Rs. 390. Find the number of years.  Select.
A) 3.5  B) 3.75  C) 4  D) 3.9  E) 4.5

Rationale: ( 1000 xtx 3 / 100 ) + ( 1400 xtx 5 / 100 ) = 390 â † ’ t = 3.9 answer d
Answer: D