Final answer:
After calculating the costs for both car rentals, it is determined that after approximately 4 hours, renting from Easy car rental is less expensive than renting from Zap's car rental. This conclusion is reached by finding the break-even point where the cost functions of both rentals are equal.
Step-by-step explanation:
To determine after how many hours it is less expensive to rent from Easy car rental compared to Zap's car rental, we need to establish the cost functions for both rental services and find the point at which the two costs are the same.
Zap's car rental charges a constant rate of $15.00 per hour. Therefore, the cost function for Zap's car rental is Z(h) = 15h, where h is the number of hours.
Easy car rental's cost function takes into account both the hourly rate and a one-time rental fee: E(h) = 8.50h + 25.50.
We find the break-even point where Z(h) = E(h):
15h = 8.50h + 25.50.
Solving for h gives us:
15h - 8.50h = 25.50
h = 25.50 / (15 - 8.50)
Doing the calculation:
h = 25.50 / 6.50
h = 3.9231 hours
Therefore, after approximately 4 hours (to the nearest hour), it is less expensive to rent from Easy car rental.