Ronald is setting up an aquarium in his new office. At one pet store, fish cost $2 each and an aquarium cost $40. At another pet store, fish cost $3 each and an aquarium cost $36.
a. Write and solve a system of equations to represent the cost y of x fish and an aquarium at each store.
b. Solve this system using substitution or elimination.
c. What does this solution represent?
d. If Ronald wants 5 fish, from which pet store should he buy his aquarium? Explain.