A sum, when invested at 10% simple interest per annum, amounts to ₹5040 after 4 years. What is the simple interest (in ₹) on the same sum at the same rate of interest in 1 year?

Correct option is C

Given:

Amount after 4 years = ₹5040

Simple Interest rate = 10% per annum

Time = 4 years

Formula Used:

Amount=Principal + Simple Interest

Simple Interest =$$\frac{P \times R \times T}{100}$$​

Where:

P is the principal

R is the rate of interest

T is the time period

Solution:

Amount = P +$$\frac{P \times R \times T}{100}$$​

5040 $$= P + \frac{P \times 10 \times 4}{100}$$​

5040 = P +$$\frac{40P}{100}$$​

5040 = P $$\left(1 + 0.4\right)$$​​

5040 = P$$\times 1.4$$​

P =$$\frac{5040}{1.4} = 3600$$​

So, the principal is ₹3600.

For 1 year:

Simple Interest=$$\frac{3600 \times 10 \times 1}{100}$$​

Simple Interest =$$\frac{36000}{100} = ₹360$$​

Thus, the simple interest on the same sum at the same rate for 1 year is ₹360.