New Enroll in RBI Grade B New Batch - Starts on May 21

    Question

    'P' is 25% less efficient than 'Q'. 'Q' takes 20 days less

    than 'P' to complete the same task. Find how much time 'Q' will take to complete the work if he works at 75% of his efficiency.
    A 50 days Correct Answer Incorrect Answer
    B 28 days Correct Answer Incorrect Answer
    C 80 days Correct Answer Incorrect Answer
    D 65 days Correct Answer Incorrect Answer

    Solution

    ATQ,

    Let the efficiency of 'Q' be '10x' units/day

    So, efficiency of 'P' = 10x × 0.75 = '7.5x' units/day

    So, ratio of efficiency of time taken by 'P' and 'Q' = 10x : 7.5x = 4 : 3

    Let time taken by 'P' and 'Q' be '4y' days and '3y' days

    So, 4y - 3y = 20

    So, y = 20

    Time taken by Q to finish the work = 3 × 20 = 60 days

    So, required time = 60 ÷ 0.75 = 80 days

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