Question

Rohan pays an interest of Rs1500 for 4 years on a sum of Rs 2500, find the rate of interest per annum(p.a.).

Answer 1

Answer :-

• The rate is 15℅ per annum.

Given :-

• Principal = Rs 2500.
• Time = 4 years.
• Simple interest = Rs 1500.

To find :-

• The rate of interest per annum.

Step-by-step explanation :-

The question has given us the principal, simple interest and time. We have to find the rate of interest per annum.

We know that :-

$\boxed{ \sf SI = \dfrac{P \times R \times T}{100} }$

We will apply this formula to find the rate of interest per annum.

Let the rate be r.

Then according to the formula,

$\sf1500 = \dfrac{25 \!\!\!\not0 \!\!\!\not0 \times r \times 4}{1 \!\!\!\not0 \!\!\!\not0}$

Reducing the numbers,

$\sf1500 = \dfrac{25 \times r \times 4}{1}$

Multiplying the constants and removing the denominator, since when the denominator is 1, it can be ignored.

$\sf1500 = 100 \times r$

Multiplying 100 by r,

$\sf1500 = 100r$

Transposing 100 from LHS to RHS, changing it's sign,

$\sf \dfrac{1500}{100} = r$

Dividing 1500 by 100,

$\sf15 = r$

$\sf r = 15.$

So, the rate of interest per annum is 15℅.