A sum of money at simple interest amounts to Rs. 1072 in 2 years and to Rs. 1144 in 4 years. The sum is:	Choose the correct option
A) rs . 1000 B) rs . 850 C) rs . 500 D) rs . 1200 E) rs . 900

Rationale: "s . i . for 2 years = rs . ( 1144 - 1072 ) = rs . 72 . s . i . for 1 year = rs . 72 / 2 = rs . 36 . principal = rs . ( 1072 - 72 ) = rs . 1000 . answer : option a"
Answer: A