Q. The compound interest on 16000 Rs. for 9 months at 20% per annum, interest being compounded quarterly, is :
Answer: 2522 Rs
Notes: The interest is compounded quarterly, $latex \therefore R = \frac{20}{4} = 5\%&s=1$ Time = 3 quarters $latex \therefore C.I. = P\left [ \left ( 1+\frac{R}{100} \right )^{T} - 1 \right ]&s=1$ $latex = 16000\left [ \left ( 1+\frac{5}{100} \right )^{3} - 1 \right ]&s=1$ $latex = 16000\left [ \left ( \frac{21}{20} \right )^{3} - 1 \right ]&s=1$ $latex = 16000\left ( \frac{9261 - 8000}{8000} \right )&s=1$ $latex = 16000\times \frac{1261}{8000} = 2522 Rs.&s=1$ Hence option [C] is correct answer.

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