A sum of money lent out at S.I. amounts to Rs. 660 after 2 years and to Rs. 1020 after a further period of 5 years. The sum is? Select.
A) s . 440 B) s . 500 C) s . 540 D) s . 740 E) s . 516

Rationale: "s . i for 5 years = ( 1020 - 660 ) = rs . 360 . s . i . for 2 years = 360 / 5 * 2 = rs . 144 . principal = ( 660 - 144 ) = rs . 516 . answer : e"
Answer: E