A sum, when invested at 20% simple interest per annum, amounts to ₹2160 after 4 years. What is the simple interest (in ₹)on the same sum at the same rate in 2 year?

Correct option is B

Given:

Amount after 4 years = ₹2160.

Rate of interest = 20% per annum.

Time = 4 years.

Formula Used:

Simple Interest formula:

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

Amount = Principal + Simple Interest.

Solution:

Amount after 4 years:

​$$2160 = P + \frac{P \times 20 \times 4}{100}\\ \ \\2160 = P + \frac{80P}{100} \\ \ \\2160 = P + 0.8P \\ \ \\2160 = 1.8P\\ \ \\P = \frac{2160}{1.8} = 1200$$​​

Simple Interest for 2 years:

SI = $$\frac{1200 \times 20 \times 2}{100} = \frac{48000}{100} = 480$$​​