Question

A sum of money becomes 8/5 of itself in 5 years at a certain rate of simple interest. Find the rate of interest???​

Answer 1

Answer : 12%

explanation :

Let the sum of money be P(which is the principal value) and rate of interest be R.

According to the question,

Amount (principal +simple interest) = 8P/5

Time (T) = 5 years

Simple interest (SI) = PRT/100

SI = 5PR/100

Amount = P +SI

8P/5 = P+(5PR/100)

8P/5 = P(100+5R)/100

160 = 100 +5R

5R =60

R = 12

Therefore, rate of interest = 12% p.a.

Answer 2

The rate of intrest is 5 because i said so