You drive along the highway at a constant speed of 45 miles per hour. How far do you travel in 5.3 hours? In 8.5 hours?
In this case the distance you travel is the dependent variable because it depends on the time. The time is the independent variable because it passes independently. You can write related variables in the form of an ordered pair, with the independent variable first and the dependent variable second: (time, distance).
Note that the speed of the car is the rate of change, and the number of hours driven is the change in the independent variable. To solve the problem, multiply the speed in miles per hour by the time ( in hours).
You drive at a constant speed of 45 miles per hour.
Write the function.
y = 45x
To find how far you travel in 5.3 hours, substitute 5.3 for x in the equation.
y = 45(5.3)
Thus , in 5.3 hours, you travel 238.5 miles.
To find how far you travel in 8.5 hours, substitute 8.5 for x in the equation.
y = 45(8.5)
Thus, in 8.5 hours, you travel 38.5 miles.