Simple Interest Questions and Answers

Given, principal = 625

Rate = 13/2%
Time = 2.5

Simple interest = p * r * t/100

= (625 * 13/2 *2.5) / 100 = 101.56

Given, principal = 800

Rate = 9%
Time = 1 year

Simple interest = p * r * t/100

= 800 * 9 * 1 / 100 = 72

 P = 100 * S.I / R * T

= 100 * 159.60/ 3 * 9.5 = 560

T = 100 * S.I./ P * R

= 100 * 87 / 725 * 4

= 8700/2900 = 3 years

Let the amount be Re. 1, then simple interest = 9/16 * 1

Let us assume the rate as x%, and time as x

Then, 1 * x * x /100 = 9/16

x²/100 = 9/16

16 x² = 900

x² = 900/16

x = 30/4 or 15/2

Let us assume the sum as 100 and rate as r

Then, simple interest = 100 * r * 2/100 = 2r

Simple interest on r + 3 = 100 * (r+3) * 2 / 100 = 2r + 6

Difference between two simple interest = 2r + 6 – 2r = 6

Therefore, if the difference is 6 than the sum is 100

If difference is 72, then sum = 100 * 72/6 = 1200

Principal amount + interest of three and half years = 736.50

Principal amount + interest of two years = 678

By subtracting we get, 58.50, interest for one and half year.

Therefore, interest for 2 years = 58.50 * 2 * 2/ 3 = 78

Therefore, principal amount = 678 – 78 = 600

Hence, rate = 100 * 78/600 * 2 = 6.5%

Let us assume the principal amount as p and rate as r. Since the amount doubles in 10 years, therefore simple interest is p

Therefore, p = p * r * 10/100

= 10r = 100

r = 100/10 = 10%

Rate = 100 * S.I. /p*t

= 100 * 1078/ 5600 * 3.5 = 5.5%

Therefore, simple interest on 9400 = (9400 * 21/4 * 5.5)/100 = 2714.25

Hence, amount = 12114.25

Simple interest for 1 year = simple interest for 4 years – simple interest for 3 years

806 – 767 = 39

Simple interest for 3 years = 39 * 3 = 117

Therefore, sum = 767 – 117 = 650