Question

    Person A is twice as efficient as Person B. Person B can

    complete a certain task in 32 days, while Person C takes 4 days more than Person A to finish the same task. Which of the following could be the number of days they work together such that the task remains incomplete?
    A 4 days Correct Answer Incorrect Answer
    B 6 days Correct Answer Incorrect Answer
    C 8 days Correct Answer Incorrect Answer
    D 10 days Correct Answer Incorrect Answer

    Solution

    According to the question,

    Time taken by ‘A’ to complete the work = 32/2 = 16 days

    Time taken by ‘C’ to complete the work = 16 + 4 = 20 days

    Let the total work = 160 units

    Efficiency of ‘A’ = 160/16 = 10 units/day

    Efficiency of ‘B’ = 160/32 = 5 units/day

    Efficiency of ‘C’ = 160/20 = 8 units/day

    When they work together for 7 days, work done = (10 + 5 + 8) × 7 = 161 units

    Therefore, maximum number of days they can work together such that the work doesn’t get completed is 6 days.

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