Here is my question

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.

How do you solve a question like this?

1. find the area of the unshaded square 2. find the area of the large square 3. what is the area of the frame represented by the shaded region show