<PRE><B>Question 634178</B>
Tim paints a room in 2.5 hours. Bob paints a room the same size in 5 hours. How long would it take them if they painted the room together?
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Tim time: 2.5 hrs/job ; rate = 1/2.5 job/hr
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Bob time: 5 hrs/job ; rate = 1/5 job/hr
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Together time: x hrs/job ; rate = 1/x job/hr
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Equation:
rate + rate = together rate
1/2.5 + 1/5 = 1/x
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1/(5/2) + 1/5 = 1/x
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(2/5) + 1/5 = 1/x
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3/5 = 1/x
x = 5/3  = 1 2/3 = 1 hr 40 minutes (time to do the job together)
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Comment: Post your problem again and you will probably see  a different
method for this type of problem.
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Cheers,
Stan H.
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