Word problem: Sally can paint the house in 4 hours....

mamom

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Sep 2, 2006
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Need help on how to solve this problem

Sally can paint the house in 4 hours. James can paint the house in 6 hours. If they paint it together how long will it take them?
 

Mrspi

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Dec 17, 2005
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Re: Word problem

mamom said:
Need help on how to solve this problem

Sally can paint the house in 4 hours. James can paint the house in 6 hours. If they paint it together how long will it take them?
If Sally can paint the house in 4 hours, then each hour, she paints 1/4 of the house.

If James can paint the house in 6 hours, then each hour, he paints 1/6 of the house.

Now, let x = number of hours they work together.

In x hours, Sally paints x/4 of the house, and James paints x/6 of the house.

And, what they do together in that x hours is the whole house!

So,

(x / 4) + (x / 6) = 1

Solve that for x....(hint: multlply both sides of the equation by the common denominator for the fractions)
 

mamom

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Sep 2, 2006
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is this right?

3x/12 + 2x/12 =1
5x/12=1
5x=12
x=2.4 hours
 

Denis

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Feb 17, 2004
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Yes mom: correct :idea:
 
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