Question

    Rs. 5000 when invested at simple interest of r% p.a.

    amounts to Rs. 8000 in 24 months. If the same sum had been invested for 1 year at compound interest of (r + 30) % p.a. (compounded in every 4 months), then the amount received would be?
    A 8240 Correct Answer Incorrect Answer
    B 8640 Correct Answer Incorrect Answer
    C 8340 Correct Answer Incorrect Answer
    D 8650 Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    According to the question, 8000 – 5000 = (5000 × r × 24) ÷ (12 × 100) Or, 3000 = 100 × r Or, r = 30 When the sum is invested at compound interest, Effective rate of interest = (r + 30) ÷ 3 = (30 + 30) ÷ 3 = 20% Effective time period = 1 × 3 = 3 units Amount received = Principal × {1 + (r/100)}time period = 5000 × {1 + (20/100)}3 = 5000 × (1.2)3 = 8640

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