SOLUTION: If it takes one worker 20 hours to roof a house and another 25 hours how long will it take them to work together?
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Question 349097: If it takes one worker 20 hours to roof a house and another 25 hours how long will it take them to work together? Found 2 solutions by mananth, stanbon:Answer by mananth(16949) (Show Source):
You can put this solution on YOUR website! one worker 20 hours
1/20 of the job he will do in 1 hour
another worker 25 hours to do the job
1/25 of the job in 1 hour
...
Together they will do 1/20 + 1/25 of the job in 1 hour
LCD = 100
5+4 / 100
9/100 of the job in 1 hour.
they will take 100 /9 hours to do the job.
=11.1 hours
You can put this solution on YOUR website! If it takes one worker 20 hours to roof a house and another 25 hours how long will it take them to work together?
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1st worker rate = 1/20 job/hr
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2nd worker rate = 1/25 job/hr
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Together rate = 1/x job/hr
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Equation:
rate + rate = together rate
1/20 + 1/25 = 1/x
5x + 4x = 100
9x = 100
x = 100/9 = 11 1/9 hrs (time to do the job together)
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Cheers,
Stan H.
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