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While working alone at their constant rates computer X can process 240 [#permalink]
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Updated on: 16 Dec 2014, 03:53
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A
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C
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E
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5% (low)
Question Stats:
85% (00:55) correct 15% (01:21) wrong based on 368 sessions
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While working alone at their constant rates computer X can process 240 files in 4 hours, and comp Y 240 files in 8 hrs. If all files processed by these comp. are the same size how long would it take the two comp. working at the same time at their respective constant rates , to process a total of 240 files?
A. 2hrs B. 2hrs 20 min C. 2hrs 40 min D. 6hrs E. 6hrs 20 min
i did as under X in one hour = 240/4 = 60 files Y in one hour = 240/8 = 30 fles X+ Y in one hour 60+30=90 files So together they will take (240/90)= 2 hours 40 minutes. So C is the answer. I do not know the OA. Am I right?
Re: While working alone at their constant rates computer X can process 240 [#permalink]
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29 Mar 2011, 05:14
Baten80 wrote:
While working alone at their constant rates computer X can process 240 files in 4 hours, and comp Y 240 files in 8 hrs. If all files processed by these comp. are the same size how long would it take the two comp. working at the same time at their respective constant rates , to process a total of 240 files?
2hrs 2hrs 20 min 2hrs 40 min 6hrs 6hrs 20 min
i did as under X in one hour = 240/4 = 60 files Y in one hour = 240/8 = 30 fles X+ Y in one hour 60+30=90 files So together they will take (240/90)= 2 hours 40 minutes. So C is the answer. I do not know the OA. Am I right?
Computer 1 processes 60 files an hour Computer 2 processes 30 files an hour
Combined they will process 90 files an hour
For 240 files, they will take (240/9) hours ... which is 2h40m
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Re: While working alone at their constant rates computer X can process 240 [#permalink]
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29 Mar 2011, 05:47
Baten80 wrote:
While working alone at their constant rates computer X can process 240 files in 4 hours, and comp Y 240 files in 8 hrs. If all files processed by these comp. are the same size how long would it take the two comp. working at the same time at their respective constant rates , to process a total of 240 files?
2hrs 2hrs 20 min 2hrs 40 min 6hrs 6hrs 20 min
i did as under X in one hour = 240/4 = 60 files Y in one hour = 240/8 = 30 fles X+ Y in one hour 60+30=90 files So together they will take (240/90)= 2 hours 40 minutes. So C is the answer. I do not know the OA. Am I right?
Re: While working alone at their constant rates computer X can process 240 [#permalink]
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06 Apr 2011, 07:25
1
X - 60 files per hour Y - 30 files per hour X & Y together - 90 files per hour 90+90=180 We need 60 more So 60/90 of an hour i.e. 2/3 of an hour = 40 min So 2 hours and 40 min...
Re: While working alone at their constant rates computer X can process 240 [#permalink]
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05 Nov 2017, 08:21
Baten80 wrote:
While working alone at their constant rates computer X can process 240 files in 4 hours, and comp Y 240 files in 8 hrs. If all files processed by these comp. are the same size how long would it take the two comp. working at the same time at their respective constant rates , to process a total of 240 files?
A. 2hrs B. 2hrs 20 min C. 2hrs 40 min D. 6hrs E. 6hrs 20 min
The rate of computer X is 240/4 = 60 files in 1 hour and the rate of computer Y is 240/8 = 30 files in 1 hour, so the combined rate is 90 files in 1 hour. Thus, it takes 240/90 = 2 60/90 hours = 2 ⅔ hours = 2 hours and 40 minutes to complete 240 files when both computers work together.
Answer: C
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