Question 624842
Amount of work = (Rate per Person) * (Number of Persons) * (Number of days)
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Assuming that all involved people can work the same rate as the others, we solve first for the rate <i>(what part of the work is each one able to finish in a given amount of time)</i> per person.
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(Rate Per Person) =  (Amount of Work) / ( (Number of Persons)*(number of days))
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Since there is only 1 job to be done, (Amount of Work) = 1. We plug in the other values to solve for the rate per person.
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(Rate per Person) = (1) / ((3)*(3))
(Rate per Person) = 1 / 9
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Since the question asks for the number of days two people can finish the same job, we come up with the equation based on the original:
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(Number of days) = (Amount of Work) / ((Rate per Person) * (Number of Persons))
(Number of days) = 1 / ((1/9)*2)
(Number of days) = 1 / (2/9)
(Number of days) = 9/2 = <b>4.5 days</b>

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Two people can finish the job in 4 1/2 days.