What is the range of an inverse exponential function?

Based on what i know about mean, this doesn't add up.

Omar is going on a road trip! the car rental company offers him two types of cars. each car has a fixed price, but he also needs to consider the cost of fuel. the first car costs $90 to rent, and because of its fuel consumption rate, there's an additional cost of s0.50 per kilometer driven.

700 miles the train takes 5 hours to a travel the distance at what unit rate is the train traveling?