A sum, when invested at 10% simple interest per annum, amounts to ₹2160 after 2 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 2 years = ₹2160

Rate of interest = 10% per annum

Time = 2 years

Formula Used:

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

Amount = P + SI

Solution:
Let the principal be P.

The amount after 2 years is ₹2160, and the rate of interest is 10%, with the time period being 2 years.
The formula for the amount is:

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

Substitute the given values:

2160 = P + $$\frac{P \times 10 \times 2}{100}$$​

2160 = P + 0.2P

2160 = 1.2P

P =$$\frac{2160}{1.2}$$​= 1800

So, the principal is ₹1800.

Now, to find the simple interest for 1 year, we use the formula for simple interest:

SI =$$\frac{1800 \times 10 \times 1}{100}$$​=$$\frac{18000}{100}$$​ = 180

So, the simple interest for 1 year is ₹180.