- Principal:The money borrowed or lent out for a certain period is called the principal or the sum.
- Interest:Extra money paid for using other’s money is called interest.
- Simple Interest (S.I.):If the interest on a sum borrowed for certain period is reckoned uniformly, then it is called simple interest.Let Principal = P, Rate = R% per annum (p.a.) and Time = T years. Then
(i). Simple Intereest = 
P x R x T 
100 (ii). P = 100 x S.I. ; R = 100 x S.I. and T = 100 x S.I. . R x T P x T P x R Simple Interest – General Question
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.
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 = 45000x = 7500.So, sum invested in Scheme B = Rs. (13900 – 7500) = Rs. 6400.
Tips and Tricks to solve Simple Interest Problems
Principal = Rs. (815 – 117) = Rs. 698.
