A sum of money at simple interest amounts to Rs. 815 in 3 years and to Rs. 854 in 4 years. The sum is :  Choose the correct choice.
A) Rs. 700 B) Rs. 690 C) Rs. 650 D) Rs. 698 E) Rs. 765
Explanation:   Simple Interest (SI) for 1 year = 854-815= 
<gadget id="calculator">854-815</gadget>
<output>39</output>
39   Simple Interest (SI) for 3 years= 39 × 3 = 117   Principal = 815 - 117 = Rs.698   Answer: Option Rs. 698
<result>D</result>
A sum of money at simple interest amounts to Rs. 815 in 3 years and to Rs. 854 in 4 years. The sum is :