Simple Interest

1.  A sum of money at simple interest amounts to Rs. 815 in 3 years and to Rs. 854 in 4 years. The sum is: A. Rs. 650 B. Rs. 690 C. Rs. 698 D. Rs. 700 Answer: Option C Explanation: S.I. for 1 year = Rs. (854 - 815) = Rs. 39. S.I. for 3 years = Rs.(39 x 3) = Rs. 117.  Principal = Rs. (815 - 117) = Rs. 698. 2.  Mr. Thomas invested an amount of Rs. 13,900 divided in two different schemes A and B at the simple interest rate of 14% p.a. and 11% p.a. respectively. If the total amount of simple interest earned in 2 years be Rs. 3508, what was the amount invested in Scheme B? A. Rs. 6400 B. Rs. 6500 C. Rs. 7200 D. Rs. 7500 E. None of these Answer: Option A Explanation: Let the sum invested in Scheme A be Rs. x and that in Scheme B be Rs. (13900 - x). Then, x x 14 x 2 + (13900 - x) x 11 x 2 = 3508 100 100  28x - 22x = 350800 - (13900 x 22)  6x = 45000  x = 7500. So, sum invested in Scheme B = Rs. (13900 - 7500) = Rs. 6400.