Question

If rs 4 becomes rs. 10 in 50 years at simple interest., then rate of interest is​

Answer 1

We know that simple interest = prt/100
here
Principal (p)= 4
rate of interest per annum (r)= r
Time(t)=50

4×r×50/100=10
200r/100=10
2r=10
r = 5%

Answer 2

The rate of interest is 3%.

Given: Rupees 4 becomes rs. 10 in 50 years at simple interest.

To find: We have to find the rate of interest.

Solution:

The formula of simple interest is-

$\frac{prt}{100}$

Where p is the principal amount which is equal to 4.

t is a period that is equal to 50 years.

r is the rate of interest.

The interest will be 10-4=6.

Thus putting this value in the formula we get-

$6 = \frac{4 \times r \times 50}{100} \\ r = 3\%$

The rate of interest is 3%.