Re: Linda takes 4 hours to do a job, whereas Bob
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23 Jul 2019, 06:14
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