Question

    The C.I on a sum of Rs. 6400 becomes Rs. 1276.5625 in 9 months. Find the rate of interest, if the rate of interest is compounded quarterly?

    A 15% p.a Correct Answer Incorrect Answer
    B 12% p.a Correct Answer Incorrect Answer
    C 25% p.a Correct Answer Incorrect Answer
    D 21% p.a Correct Answer Incorrect Answer

    Solution

    P = Rs 6400 T = 9 months = 3/4 years C.I = Rs 1276.5625 Amount = C.I + P Amount = 6400 + 1276.5625 Amount = Rs 7676.5625 A = P`(1+r/(4xx100))` 4t 7676.5625 = 6400`(1+r/400)^(4xx3/4)` `76765625/64000000` =`(1+r/400)` 3 `614125/512000` = `((400+r)/400)` 3 `(85/80)^3` = `((400+r)/400)` 3 `85/80` =`(400+r)/400` 85 × 5 = 400 + r r = 425 – 400 r = 25% p.a

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