??? Do you realize that you are saying that, working together, they work no faster than when Melanie works by herself? There is no "equation" here- you just want to add the two rates together to find how fast they work together. What is 1/x+ 1/2x ?

And another thing- don't just write "Melanie= 1/x". The girl is not a number. Write "the rate at which Melanie paints the barn = 1/x". That makes it clear exactly what that number represents.

1/x + 1/2x = 1/x

What is the right set up?

I can evaluate when x= 5. I just need the proper rational expression.

Thanks