New SIDBI Grade A New Batch Starts on Nov 18

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    Question

    ‘M’ is 60% more efficient than ‘N’. ‘N’ started the work alone and worked for 20 days and after that ‘N’ is replaced by ‘M’. If the total work is completed in 30 days, find the time taken by ‘M’ to finish the same work alone?

    A 20.5 days Correct Answer Incorrect Answer
    B 21.5 days Correct Answer Incorrect Answer
    C 22.5 days Correct Answer Incorrect Answer
    D 17.5 days Correct Answer Incorrect Answer

    Solution

    Let the efficiency of ‘N’ = ‘5x’ units/day Efficiency of ‘M’ = ‘8x’ units/day Time taken by ‘M’ to complete the remaining work = 30 – 20 = 10 days Total work = 20 × 5x + 10 × 8x = 180x units Desired time = 180x/8x = 22.5 days

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