The equation for car 2 is represented below as

Where,

To calculate the average speed of each car, we will have to calculate the slope of the line
For car 2, when x= 1 hr

When x=4 hrs,

The average speed of car 2 will be calculated using the formula below

By substituting the values, we will have

Hence,
The average speed of car 2 is 55 miles/hr
For car 1, when the value of x=1 hr

When the value of x = 4hrs

To calculate the average speed of Car 1 we will use the formula below

Hence,
The average speed of car 1 is 64 miles/hr
Therefore,
Car 1 is travelling at a greater speed