Question

Find the sum that amounts to Rs 9,144 in 3 years at 9% per year simple interest.​

Answer 1

Given:

Amount = Rs. 9,144

Time = 3 years.

Rate of simple interest = 9%

To find:

The principal value.

Solution:

The formula for simple interest is:

$I=\dfrac{P\times r\times t}{100}$

Where, P is principal, r is the simple rate of interest, and t is the number of years.

Putting $r=9,t=3$ in the above formula, we get

$I=\dfrac{P\times 9\times 3}{100}$

$I=\dfrac{27P}{100}$

$I=0.27P$

We know that,

$\text{Amount}=\text{Principal + Interest}$

$9144=P+0.27P$

$9144=1.27P$

Divide both sides by 1.27, we get

$\dfrac{9144}{1.27}=P$

$7200=P$

Therefore, the principal value is Rs. 7200.