I think that the minimum obligatory rental time for the tennis court is 2 hours.
In this case the algebric equation for the cost c in terms of rental hours will be as follows:
C = 40 + 5(H - 2) Where c is the total cost and H is the rental hours. H should be > = 2 since the minimum
rental time is 2 hours.
The cost for 5 hours will be:
C= 40 + 5(5 - 2) = 40 + 5(3)= 40 + 15 = 55