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Ken can write all the boring word problems for this book in l0 hours.After he has...

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Ken can write all the boring word problems for this book in l0 hours.
After he has worked 2 hours, Steve comes to help him and together they finish the problems in 3 more hours. How many hours would it have taken steve
working aloneP

Posted by ltop on October 21, 2013 at 7:38 PM via web and tagged with hours, math

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Ken needs 10 hours to finish the job so in one hour he can do `1/10` of the job. After he's been working for 2 hours there are still `8/10` of the job unfinished which he and Steve finish in 3 hours.

`8/10=3cdot1/10+3cdot s`

`s` is the amount of work done by Steve in one hour.

`3s=8/10-3/10`

`3s=1/2`

`s=1/6`

So in one hour Steve can do `1/6` of the job hence he would finish the job in 6 hours if he worked alone.

Posted by tiburtius on October 21, 2013 at 9:42 PM (Answer #1)