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Mathematics 11 Online
OpenStudy (okdutchman7):

Please help. WILL MEDAL! @mathmale @surjithayer @ganeshie8 @Hero @Kainui @TheSmartOne @Preetha @SolomonZelman @zepdrix @rebeccaxhawaii @Vocaloid @Miracrown @dtan5457

OpenStudy (okdutchman7):

The big man could do 1/3 of a job in 4 hours. The little man could do 1/2 of a job in 2 hours. If the little man needed to complete 30 jobs and worked for 2 hours alone and then was joined by the big man, how long did it take them both to finish the remaining jobs?

OpenStudy (loser66):

Total is 30 jobs, right?

OpenStudy (okdutchman7):

Yes

OpenStudy (okdutchman7):

The rate of the big man is 1/12

OpenStudy (loser66):

Little man does 1/2 job in 2 hours, and he does alone in 2 hours. That means, the leftover is 29.5 jobs, ok?

OpenStudy (okdutchman7):

The rate of the little man is 1/4

OpenStudy (okdutchman7):

Yes.

OpenStudy (okdutchman7):

Their combined rate is 1 job/ 3 hours

OpenStudy (okdutchman7):

So I have to find how long it will take both of them to complete 29.5 jobs with a combined rate of 1/3

OpenStudy (loser66):

Now, for 29.5 jobs. The Little man work 1/2 job in 2 hours. Hence, to finish 1 job, he has to spend 4 hours, ok?

OpenStudy (okdutchman7):

Understood.

OpenStudy (loser66):

so, in 12 hours, how many jobs has he done?

OpenStudy (okdutchman7):

3 jobs

OpenStudy (okdutchman7):

But the 2 of them combined can do 4 jobs

OpenStudy (loser66):

ok now for the Big man, he needs 12 hours to finish 1 jobs. Hence in 12 hours, both combine to get 4 jobs done. right?

OpenStudy (okdutchman7):

yes

OpenStudy (loser66):

So, in 84 hours, they get 28jobs done.

OpenStudy (okdutchman7):

That's correct

OpenStudy (loser66):

12 hours /4 jobs 1 jobs/ 3 hours

OpenStudy (loser66):

1.5 jobs/4.5 hours, right?

OpenStudy (okdutchman7):

1.5 jobs in 4.5 hours

OpenStudy (okdutchman7):

Yep

OpenStudy (loser66):

so, combine all, they need 88 hours 30 minutes, right?

OpenStudy (okdutchman7):

That's right, Thank You!

OpenStudy (loser66):

ok

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