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1)It's a very common problem for me .

I don't get when do I have to multiply or divide a fraction in unitary method e.g.

10 men do 1 work in 40 days

10 men does 3/4 work in 40*3/4 days

or should i do 10 men does 3/4 work in 40*4/3 days

I do't undestand!Plz give me a reason why should I multiply or divide it.

I would be very grateful if anybody does so!

2)The problem:

Forty men finish a piece of work in 40 days; if % men leave the work every ten days,in what time will the whole work be completed.

My try:

I tried to put it like this

40 men in 40 days does 1 work

40 men in 1 day does 1/40 work

40 men in 10 day does 1/40 *10work=1/4

But if I do so I becomes a very very long method.

Isn't there any shorter way.

Please help!

Thank you.

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# Homework Help: Fraction problem

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