Problema Solution
Mr Roper handles 50 apartment units.
When the rent is $450 per month, all units are occupied.
However, on the average, for each $5 increase in rent, one unit becomes vacant.
The number of units rented, N, is a function of the rental price, p.
Answer provided by our tutors
we require that p >= 450 since no information is given on what happens if the price falls below $450:
N = 50 - (p-450)/5