Q51
A certain some of money and Rs. 2420 in 2 years and Rs. 2662 in 3 years at same rate of compound interest, compounded annually. The rate of interest per annum is = ?
A.
6%
B.
8%
C.
9%
D.
10%
AnswerAnswer: Option D
Solution
Answer: Option D
Solution:
\begin{aligned}
& {\text{Amount after three years}} \\
& {\text{ = Rs. 2662}} \\
& {\text{Amount after two years}} \\
& {\text{ = Rs. 2420}} \\
& {\text{Net interest earned in the }}{{\text{3}}^{{\text{rd}}}}{\text{ year}} \\
& {\text{ = }}\,{\text{2662}} - {\text{2420}} \\
& {\text{ = Rs}}{\text{. 242}} \\
& {\text{Rate of interest (r)}} \\
& {\text{ = }}\frac{{242}}{{2420}} \times {\text{100 = 10% }} \\\end{aligned}(∴ 2nd year's amount is principal for 3rd year)