Question

    C is 37.5% more efficient than A, and A is 60% more

    efficient than B. If A, B, and C together can complete a task in 40 days, how long will it take A alone to complete 75% of the task?
    A 100 days Correct Answer Incorrect Answer
    B 60 days Correct Answer Incorrect Answer
    C 90 days Correct Answer Incorrect Answer
    D 120 days Correct Answer Incorrect Answer

    Solution

    Let efficiency of ‘B’ ‘5x’ units per day

    Efficiency of ‘A’ = 1.60 × 5x = 8x units per day

    Efficiency of ‘C’ = 1.375 × 8x = 11x units per day

    Total work = (3x + 8x + 11x) × 40 = 960x units

    Desired time = (0.75 × 960x)/8x = 90 days

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