NET Math Help

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I've been reviewing math problems, and I'm stuck on a particular type of question. I know someone answered this question in the past few months but I can't seem to find the post anymore! Any help would be greatly appreciated--I'm feeling pretty dumb since I passed calculus but can't remember how to set up this problem!

If Sam can do a job in 4 days that takes Lisa 6 days and Tom 2 days, how long would the job take if Sam, Lisa and Tom worked together to complete it?

Please help me be one of the few who get an interview!

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Specializes in Home Care.

Don't you just calculate the average number of days? Or is that just too easy? LOL

4 + 6 + 2 = 12

12/3 = 4

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The answer is 1.09, so it's not an average.

I do like my coworker's answer, though. You fire Lisa because she's taking so long, and you fire Tom because he's making Sam look bad... so the answer is 4. :)

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Specializes in Home Care.

oh wow, I've no idea how you came up with that answer. What is the formula?

I like your co-worker's answer too :)

What kind of application requires you to know that math?

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I don't know the formula but I would think it through if all three of them work one day then Tom can finish 1/2 (0.5) the job in one day Sam can finish 1/4th (0.25) of the job and Lisa can finish 1/6th (0.16) of the job.

0.5

0.25

0.16

0.91 or 91% of the job would be finished by all three in one day

this leaves 0.09 or 9% of the job to be finished the next day

There may be some kind of formula for this but if there is I have forgotten it.

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tlc2u, thanks, that makes sense! It's not extra scientific but should be perfect for picking out the right multiple choice answer.

I'm studying for the NET, and I encountered several problems like this. I only know the answer is 1.09 because that's what the answer key said. :)

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I googled this word problem and here is what I found.

If you look at it this way.

1job/6days - Lisa = 2jobs/12days

1job/4days - Sam = 3jobs/12days

1job/2days - Tom = 6jobs/12days

A total of 11jobs/12days = 1job/xdays

12*1 = 11x

x=12/11 or 1.09days

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this question is not even on the NET so i wouldn't worry about this type of math.

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