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A man can do a certain task in 21 hours, another can do t...
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by
WinpossibleUser3637
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A man can do a certain task in 21 hours, another can do the task in 28 hours, and a boy can do the task in 48 hours. How long will it take to do the task if all work together?
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Responses
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Every hour 1st man does 1/21 of the task, 2nd man does 1/28 of the task and the boy does 1/48 of it.
So that means, every hour (1/21) + (1/28) + (1/48) of the task gets done = 5/48.
So if we set up a ratio (amount of task : hours)
5/48 : 1
5 : 48
1 : 9.6
So they will finish the task in 9.6 hours.
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by
Winpossible
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Aug 25, 10 02:52AM PST
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