Start with: 12p + 15 c > 360. Consider 12p + 15c = 360.
If p = 0: c = 24. If c = 0 ; p = 30. Now you have two points to plot: (0 , 24) and (30 ,0).
If you send me a request I'll Show You the Algebra.
Copy this web address: http://itools.subhashbose.com/grapher/index.php
Paste it into your address bar and plug in the two points. You will see a graph.
You have to shade the graph to solve your problem.
In this case choose (0 ,0) as your "Test Point" (anything you dont understand about my explination send me a request and I'll answer)
12(0) + 15(0) > 360 implies that 0 >360 which is false so shade the side of the line not cpntaining that point. I this case that will be the "top half " also since the inequality is strict when you redraw the graph you'll want to use a dashed line to indicate that values on the line itself are not included.