SOLUTION: Please help me solve this so I can show my daughter.
It takes Sandra 15 hours to complete a job. Garland can complete the job in 12 hours. How long will it take them to do the
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It takes Sandra 15 hours to complete a job. Garland can complete the job in 12 hours. How long will it take them to do the
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Question 1107566: Please help me solve this so I can show my daughter.
It takes Sandra 15 hours to complete a job. Garland can complete the job in 12 hours. How long will it take them to do the job working together?
THank you. Found 2 solutions by josgarithmetic, ikleyn:Answer by josgarithmetic(39618) (Show Source):
Since "It takes Sandra 15 hours to complete a job", she makes of the job per hour.
It is her "rate of work".
Since "Garland can complete the job in 12 hours", he makes of the job per hour.
It is his "rate of work".
Working together, they make + part of the job per hour.
It is their combined rate of work.
+ = = = .
Thus they make of the work per hour. Every hour.
Hence, it will take them hours = hours = 6 hours and 40 minutes to complete the job working together.
Solved.
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It is a typical joint work problem.
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