The equation for the motion of the faster car can be written as:
y = mx + b
where:
m = slope (speed of the car)
b = y-intercept (starting point of the car)
To find the slope, we can use the formula:
m = (y2 - y1) / (x2 - x1)
Let's use the information given:
On Road 1, the car can go 60 miles in 2 hours. This can be represented as (x1, y1) = (2, 60).
On Road 2, the car can go 90 miles in 4 hours. This can be represented as (x2, y2) = (4, 90).
Substituting these values into the slope formula:
m = (90 - 60) / (4 - 2)
m = 30 / 2
m = 15
Now that we have the slope, we can choose any of the given points to find the y-intercept.
Let's use (x2, y2) = (4, 90):
90 = 15(4) + b
90 = 60 + b
b = 90 - 60
b = 30
Therefore, the equation representing the motion of the faster car is:
y = 15x + 30