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    Question

    A and B alone can complete a work in 15 and 30 days,

    respectively. 50% of the work is completed by C in 2x days, and the remaining work is completed by A and B working together in ‘x’ days. Find the time taken by B and C to complete the whole work while working together.
    A 12 days Correct Answer Incorrect Answer
    B 15 days Correct Answer Incorrect Answer
    C 14 days Correct Answer Incorrect Answer
    D 18 days Correct Answer Incorrect Answer
    E 10 days Correct Answer Incorrect Answer

    Solution

    Time taken by A and B to complete the whole work while working together = (15 × 30)/(15 + 30) = 10 days So, x = 10/2 = 5 (Since, 50% of the work is done by A and B together) As, time taken by C to complete 50% of the work = 5 × 2 = 10 days So, time taken by C to complete the entire work = 10 × 2 = 20 days Therefore, time taken by B and C to complete the whole work while working together = (20 × 30)/(20 + 30) = 12 days

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