We are given that a truck driver averages 60 mph while delivering freight, and 45 mph when going back. The total driving time is 7 hours. We want to find how long each trip takes.
To calculate the time each trip takes, we will need to use the Distance Formula.
Distance=(Rate)(Time) ⇒ d=r* t
If we let t be the time the shorter trip takes, then the longer trip will take 7-t hours, since both trips took 7 hours in total. By substituting the respective times and rates we can write equations describing the completed distance for both legs of the journey.
First Leg:& 60t
Second Leg:& 45(7-t)
We know that the completed distances will be the same since the driver takes the same route, only changing the direction.
First Leg&= Second Leg
60t&= 45(7-t)
Since t represented the time needed for the driver to reach the delivering site, we know that it took 3 hours for the truck driver to get there. Let's now calculate the time needed to go back.
