A sum of money at simple interest amounts to Rs. 825 in 3 years and to Rs. 846 in 4 years. The sum is?  Choose the correct option.
A) s. 738 B) s. 638 C) s. 650 D) s. 762 E) s. 735
S.I. for 1 year = (846 - 825) = Rs. 29   S.I. for 3 years = 21 * 3 = Rs. 63   Principal = (825 - 63) = Rs. 762.   ANSWER:s. 762
<result>D</result>
A sum of money at simple interest amounts to Rs. 825 in 3 years and to Rs. 846 in 4 years. The sum is?