Can someone please help. I tried to solve it and I keep getting stuck or can someone at least help me start off solving it?
An advertising company charges $40 per half-page advertisement and $75 per full-page advertisement
Michael has a budget of $800 to purchase 13 advertisements.

(a) Define a variable for each unknown
Write a system of equations to represent the situation and solve the system

(b) How many half-page advertisements does Michael purchase?
Show your work.

(c) How many full-page advertisements does Michael purchase?