Question

a sum of money 4 times in 20 years at simple interest find the rate of interest​

Answer 1

Answer:

use the formula of simple interest

Answer 2

Answer:

Let Principal is P

A=P (1+rt)

After 20 years A=4P

So 4P=P (1+r20)

Dividing both sides by P

4=1+20r

4-1=20r. 20r=3

r=3/20

Converting into percentage

r=3/20 × 100

r=15

2nd example

The answer is 15%

Verification:

Let the amount be P.

Interest at 15% on ‘P’ for 20 years will be = P x 20 X 15% = 3 P

After 20 years, the Principle amount + Interest will be P + 3P = 4 P

The sum, at 15% interest, becomes 4 times after 20 years .

Please mark me as brainliest

Thank you and have a nice day