Question

    The compound interest on a certain sum for 2 years at

    10% per annum is Rs. (x+420). The simple interest on the same sum at the same rate for the same time is Rs. 600. Find the value of x.
    A 200 Correct Answer Incorrect Answer
    B 230 Correct Answer Incorrect Answer
    C 240 Correct Answer Incorrect Answer
    D 210 Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    Let the principal be P. Simple interest (SI) = P × R × T / 100 = P × 10 × 2 / 100 = 600 P = Rs. 3,000 Compound interest (CI) = P × (1 + R/100)^T - P CI = 3000(1 + 10/100)^2 - 3000 = 3000 × 1.21 - 3000 = 3,630 - 3,000 = Rs. 630 According to the question, CI = Rs. (x + 420) x + 420 = 630 x = 210

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