Answer:
a) 12x + 20y = 300
b) No
Explanation:
You can define your variables however you like. Let x = number of caps and y = number of shirts.
Using the costs given the equation would be
12x + 20y = 300.
For part b the answer is no, only points with positive x and y values would be solutions, since you cannot have a negative number of caps or shirts.