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    Question

    Amit can do certain work alone in 'w' days. Arjit can do

    the same work alone in (w + 12) days.Gaurav started working and did (1/2) the work at the efficiency of Amit and rest work at efficiency of Arjit, and finished the work in 24 days. Then, find the value of (w2 + 5w -40)
    A 450 Correct Answer Incorrect Answer
    B 650 Correct Answer Incorrect Answer
    C 370 Correct Answer Incorrect Answer
    D 374 Correct Answer Incorrect Answer
    E none of these Correct Answer Incorrect Answer

    Solution

    ATQ, we can say that Since 'Gaurav' completed (1/2) of the work with (1/2) the efficiency of 'Amit'.  So, time taken by him to complete (1/2) of the work = (w/2) days Similarly, time taken by 'Gaurav' to complete other (1/2) of the work =  [(w + 12)/2] days So, (w/2) + {(w + 12)/2} = 24 Or, w + 6 = 24 Or, w = 18 So, w2 + 5w - 40 = 324 + 90 - 40 =  324 + 50 = 374

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