Mathematics

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Twelve man take 6 hours to finish a piece of work. After the 12 men have worked for 1 hour, the contractor decides to call in 8 men so that the work can be completed earlier. How many more hours would 20 men take to complete the remaining work?

  • Mathematics -

    job requires 12(6) = 72 man-hours

    They work for 1 hour, so 12 man-hours are used up, leaving 60 man-hours for the job to be done

    Second shift has 20 men,
    so time needed to complete the job
    = 60 man-hours/20 men
    = 3 hours

    (the above applies only in theory, it does not apply to city workers or the like. Doubling the number of men on a job in practise does not cut the required time in half. , (this is supposed to be a joke) )

  • Mathematics -

    Thanks!

  • Mathematics -

    find the value of X
    if 4x+2y=5 and 3x+y=2

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