Answer
18 minutes
Work Step by Step
Let x = time working together
It takes you 30 minutes, and it takes your brother 45 minutes to rake the leaves in your yard.
If the two of you are working together: $\frac{1}{30}x+\frac{1}{45}x=1$
$\frac{3x+2x}{90}=1$
$3x+2x=90$
$5x=90$
$x=18$
It takes 18 minutes if the two of you rake the leaves when working together.
