Sapna invested ₹20,400 on simple interest, partly at the rate of 14% per annum and partly at the rate of 11% per annum. If she earns equal interests from the two investments after 9 years, then find the sum invested at the rate of 14% per annum (in ₹).

Correct option is A

Given:

Total investment = ₹20,400

Time = 9 years

Part invested at 14% = ₹x

Part invested at 11% = ₹(20400 − x)

Interests from both parts are equal

Formula Used:

Use Simple Interest formula:

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

​Solution:​

​$$\frac{x \times 14 \times 9}{100} = \frac{(20400 - x) \times 11 \times 9}{100} \\ \ \\ 14x = 11(20400 - x) \\ \ \\14x = 224400 - 11x \\ \ \\14x + 11x = 224400 \\ \ \\25x = 224400 \\ \ \ \\x = \frac{224400}{25} = ₹8,976$$​​