Answer:
36
Step-by-step explanation:
The cost of renting n movies using Plan A is ...
c = 10 +2.50n
The cost of renting n movies using Plan B is ...
c = 4 +3(n -4) . . . . for n ≥ 4
The two costs are equal when ...
4 +3(n -4) = 10 +2.50n
0.50n = 18 . . . . . . . . . . add 8 -2.50n and simplify
n = 36 . . . . . . . . . . multiply by 2
A person would have to rent 36 movies to spend the same using either plan.