Answer:
 (5, 8), (7, 1), (15, 3)
Step-by-step explanation:
a) The variables are defined in the problem statement. The total expenditure must satisfy ...
 2.00x +3.50y ≤ 42.00
b) Possible solutions include ...
 (x, y) ∈ {(5, 8), (7, 1), (15, 3)}
__
These were chosen by looking at the attached graph of the equation.