EP did a great job explaining. :))
Basically, we're setting up an equation where Option A and Option B are the same amount.
For option A, you are making 23 dollars each hours, for 40 hours. (40*23)
For option B, you are making 4% of your sales. We're looking for how much she sells, so we can write that as x. (.04x)
Set the 2 options as equal and solve for x.
=^._.^=