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Linda takes 4 hours to do a job, whereas Bob
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Updated on: 25 Jul 2019, 02:48
Updated on: 25 Jul 2019, 02:48
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Question Stats:
52% (03:09) correct
47% (03:08) wrong based on 19 sessions
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Linda takes 4 hours to do a job, whereas Bob takes 6 hours to do the same job. They worked together at their respective rates but Bob took two breaks of equal duration during the time. Despite that, the two of them were able to complete the job in 2 hours 30 minutes. What is the duration of each break that Bob took. ?
(A) 60 seconds
(B) 90 seconds
(C) 450 seconds
(D) 240 seconds
(E) 270 seconds
(A) 60 seconds
(B) 90 seconds
(C) 450 seconds
(D) 240 seconds
(E) 270 seconds
Originally posted by anuppatel012 on 21 Jul 2019, 04:45.
Last edited by Carcass on 25 Jul 2019, 02:48, edited 2 times in total.
Last edited by Carcass on 25 Jul 2019, 02:48, edited 2 times in total.
Edited by Carcass
Re: Linda takes 4 hours to do a job, whereas Bob
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22 Jul 2019, 11:37
22 Jul 2019, 11:37
Are you sure the answer isn't C, rather than D?
If I'm reading the problem correctly, C is the answer.
If I'm reading the problem correctly, C is the answer.
Re: Linda takes 4 hours to do a job, whereas Bob
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23 Jul 2019, 06:14
23 Jul 2019, 06:14
1
Linda can do 1/4 job in 1 hour and Bob can do 1/6 in 1 hour. Together, they can do 1/4+1/6= 5/12 job.
Now, in 1 hour they can do 5/12 job
In 2.5 hours they can do 5/12 * 5/2= 25/24
Form question, we have seen they have actually completed the full job in 2.5 hours. So because of Bob's break, they lost 25/24 -1 = 1/24 parts job
Bob does 1/6 job in 1 hour
Bob does 1/24 job in 6/24=1/4 hour=15 minutes
These 15 minutes equal 2 breaks Bob have taken. So the duration of break =15*60/2= 450 seconds
Now, in 1 hour they can do 5/12 job
In 2.5 hours they can do 5/12 * 5/2= 25/24
Form question, we have seen they have actually completed the full job in 2.5 hours. So because of Bob's break, they lost 25/24 -1 = 1/24 parts job
Bob does 1/6 job in 1 hour
Bob does 1/24 job in 6/24=1/4 hour=15 minutes
These 15 minutes equal 2 breaks Bob have taken. So the duration of break =15*60/2= 450 seconds
