Really difficult linear optimization problem from my book

Here is the link to the problem
http://i.imgur.com/3MDmG.jpg

I really appreciate any help on this problem.

Nevermind, I figured it out.

10hrs (max possible) of tutoring at $15/hr = $150
10hrs of delivery at $8/hr = $80
for a total of $230.
I would set up a function to be maximized, and then read through the constraints and list them:
let y= pizza hours
let x = tutor hours
then we want max of 15x + 13y, where x+y <= 20 and x <= 10. (x , y > 0).

Graph the equations, find vertices, plug vertex coordinates in to 15x +13y, find max altered vertex value.

Should leave you with 230$ possible max profit.