A sum of money at simple interest amounts to Rs. 815 in 3 years and to Rs. 844 in 4 years. The sum is:  Answers:  A) s. 650  B) s. 690  C) s. 698  D) s. 728  E) s. 760
S.I. for 1 year = Rs. (844 - 815) = Rs. 29.   S.I. for 3 years = Rs.(29 x 3) = Rs. 87.   Principal = Rs. (815 - 87) = Rs. 728.   Answer: Option s. 728
<result>D</result>
A sum of money at simple interest amounts to Rs. 815 in 3 years and to Rs. 844 in 4 years. The sum is: