Question

    A and B can complete a task in 63 days and 42 days,

    respectively. If C is 40% more efficient than the combined efficiency of A and B, how much time will C take to complete the entire task?
    A 22 days Correct Answer Incorrect Answer
    B 20 days Correct Answer Incorrect Answer
    C 18 days Correct Answer Incorrect Answer
    D 16 days Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    Let total amount of work = 126 units (LCM of 63 and 42) Efficiency of A = 126/63 = 2 units per day Efficiency of B = 126/42 = 3 units per day Efficiency of C = 1.40 × 5 = 7 units per day Desired time = 126/7 = 18 days

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