Question

A sum becomes 2.5 times in 10 years under simple interest. Find the rate.

• A. 10%
• B. 12.5%
• C. 15%
• D. 20%

Answer 1

Answer:

C. 15%

Let the principal be (P).

The amount becomes (2.5P) in 10 years.

So, the simple interest earned is:

$SI = 2.5P - P = 1.5P$

Using the simple interest formula:

$SI = \frac{P \times R \times T}{100}$

$1.5P = \frac{P \times R \times 10}{100}$

Cancelling (P):

$1.5 = \frac{10R}{100}$

$1.5 = \frac{R}{10}$

R = 15

Rate of interest = (15%) per annum. ✅