A sum of Rs. 15,000 was lent for 3 years at the rate of 4%, 5%, 6% per annum, respectively, at compound interest for the first year, second year and third year compound annually. Find the compound interest. 

Correct option is C

​$$\textbf{Given:} \\P = 15000 \\ R_1 = 4\% ,\; R_2 = 5\% ,\; R_3 = 6\% \\ Time = 3 \text{ years}\\\\textbf{Formula Used:} \\A = P\left(1+\frac{R_1}{100}\right)\left(1+\frac{R_2}{100}\right)\left(1+\frac{R_3}{100}\right)\\\ \\\textbf{Solution:}\\ A = 15000 \left(1+\frac{4}{100}\right)\left(1+\frac{5}{100}\right)\left(1+\frac{6}{100}\right) \\\ \\A = 15000 \times \frac{104}{100} \times \frac{105}{100} \times \frac{106}{100} \\A = 15000 \times \frac{1157520}{1000000} \\\ \\A = 17362.8 \\\ \\\text{Compound Interest} = A - P \\\text{Compound Interest} = 17362.8- 15000 = 2362.8 \\$$  
Exam Hall Method: