- #1

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2]if it takes martha 2 days to do a job and tina 3 days to do the same job,how long will it take both of them.

i need help not just for these questions but all.so i need a general explanation of questions like this

- Thread starter latyph
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- #1

- 8

- 0

2]if it takes martha 2 days to do a job and tina 3 days to do the same job,how long will it take both of them.

i need help not just for these questions but all.so i need a general explanation of questions like this

- #2

AKG

Science Advisor

Homework Helper

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Note that you could have broken it down the other way. If it takes 10 men 60 hrs to build 120 houses, then it takes 1 man 600 hours to build 120 houses, and so it takes him 600/120 = 5 hours to build 1 house.

Now start to answer the question (again, you can do this in two ways). If it takes 1 man 5 hours for 1 house, then it takes 1 man 5*60 = 300 hours for 60 houses, and thus it takes 5 men 300/5 = 60 hours for 60 houses. Going the other way, if it takes 1 man 5 hours for 1 house, then it takes 5 men 5/5 = 1 hour for one house, and so it takes 5 men 1*60 = 60 hours for 60 houses.

I think a general explanation might either have been too confusing, or would have just ended up giving you a formula that you could use to "plug and chug" your way through any of these problems, and if you are going to have such a formula you should figure it out yourself. But hopefully you've understood the reasoning in the above example and will be able to apply it generally.

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