SOLUTION: I am doing a rational expression application work problm for my class and I want to make sure that I do the problem correctly. My Work problm is: It takes 7 hours for will to

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: I am doing a rational expression application work problm for my class and I want to make sure that I do the problem correctly. My Work problm is: It takes 7 hours for will to      Log On


   



Question 586412: I am doing a rational expression application work problm for my class and I want to make sure that I do the problem correctly.
My Work problm is:
It takes 7 hours for will to paint a house. Judy can paint the same house in 3 hours. How long will it take them to paint the house if they work together?
Would I start my rational expression as 1/7x + 1/3x?
thank you,
mm

Found 2 solutions by scott8148, Earlsdon:
Answer by scott8148(6628) About Me  (Show Source):
Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
Not quite!
x%2F7+%2B+x%2F3+=+1 Simplify.
10x%2F21+=+1 Multiply both sides by 21.
10x+=+21 Divide by 10.
x+=+2.1
It would take them 2.1 hours or 2 hours and 6 minutes.