## gaby236 Group Title If Jim Roller can paint a room in 3 hours while John Brush would take 5 hours, how long will they take if they work together? one year ago one year ago

1. emilie.li Group Title
2. gaby236 Group Title

a;1/8 hour b;8/15 hour c; 7/8 hours

3. gaby236 Group Title

4. wio Group Title

What class is this?

5. gaby236 Group Title

math

6. wio Group Title

I know, but what level of math?

7. gaby236 Group Title

i need help

8. wio Group Title

You need to make a system of equations.

9. wio Group Title

Let, $$t$$ be the time it takes to paint the room. $$r$$ is the rate that Roller to paints it, $$b$$ is the rate that Brush paints it.

10. wio Group Title

We know that $3r = 5b$

11. wio Group Title

We also know that $(r+b)t = 3r = 5b$

12. wio Group Title

First solve for $$r$$ in terms of $$b$$ $3r=5b\implies r = \frac{5}{3}b$Now plug it into equation 2 $\left(\frac{5}{3}b+b\right)t=5b$

13. wio Group Title

Then solve for $$t$$.