Question

a sum of money becomes 7 times itself in 15 years what is the rate of interest​

Answer 1

Answer:

The rate of interest of a sum of money that becomes 7 times of itself in 15 years is 40%.

Step-by-step explanation:

The simple interest is calculated on an certain amount of money which is known as the principal, the time for which is calculated and the rate of interest.

Here let us consider the sum of money be P and the amount as given in the question is 7P

amount=principal+S.I

S.I=amount-principal=7P-P=6P

Let us assume that the rate of interest is R%

The formula for calculating the simple interest is:

$S.I=\frac{PTR}{100} \\6P=\frac{15PR}{100} \\6=\frac{15R}{100} \\R=\frac{6.100}{15} =\frac{2.100}{5} =2.20=40$

Thus the rate of interest is 40%.