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GRE Math Challenge #27-Working alone jerry can complete
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Updated on: 17 Feb 2020, 11:48
Updated on: 17 Feb 2020, 11:48
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Question Stats:
71% (02:02) correct
28% (01:53) wrong based on 59 sessions
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Working alone Jerry can complete a work in 6 minutes.Working alone ,Adam can complete a work in 8 minutes.Working together,Jerry leaves the work after 2 minutes.How long will it take Adam to complete the work?
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200 seconds
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Re: GRE Math Challenge #27-Working alone jerry can complete
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15 Nov 2015, 20:43
15 Nov 2015, 20:43
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sandy wrote:
Working alone Jerry can complete a work in 6 minutes.Working alone ,Adam can complete a work in 8 minutes.Working together,Jerry leaves the work after 2 minutes.How long will it take Adam to complete the work?
Let's assign a NICE VALUE to the job that needs to be completed.
We have completion times of 6 minutes and 8 minutes, so let's say the "job" consists of making 24 widgets (I chose this value, because 6 and 8 both divide nicely into 24)
Jerry can complete a [job] in 6 minutes
If the job is to make 24 widgets, we can see that Jerry can make 4 widgets/minute
Adam can complete a [job] in 8 minutes
If the job is to make 24 widgets, we can see that Adam can make 3 widgets/minute
Given: they work together for 2 minutes.
Together, their combined output = 4 widgets/minute + 3 widgets/minute = 7 widgets/minute
So, in 2 minutes, their TOTAL output = (2 minutes)(7 widgets/minute) = 14 widgets
If the total job is to make 24 widget, then there are still 10 widgets to make (24 - 14 = 10)
Then Jerry leaves
Adam can make 3 widgets/minute.
He must make 10 widgets
Time = output/rate = 10/3 = 10/3 minutes
Answer: 10/3 minutes or 200 seconds
Cheers,
Brent
Re: GRE Math Challenge #27-Working alone jerry can complete
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06 Jan 2016, 05:14
06 Jan 2016, 05:14
1
They work 2 min together, so jerry did 1/3 work and adam did 1/4 work. so they did 7/12 work together in 2minutes.
remained 5/12 work for adam alone, he can do this work alone in 5/12*8min*60sec=200sec.
remained 5/12 work for adam alone, he can do this work alone in 5/12*8min*60sec=200sec.
