Question 986732
A truck enters the highway driving 60 mph.
 A car enters the highway at the same place 15 minutes later and drives 68 mph in the same direction.
 From the time the car enters the highway, how long will it take the car to pass the truck?
:
Since we are dealing in mph, change 15 min to .25hrs
let t = travel time of the car
then
(t+.25) = travel time of the truck (enter highway 15 min before the car)
:
When the car catches up with the truck, they will have traveled the same distance
Write a distance equation; dist = speed * time
Car dist = truck dist
68t = 60(t+.25)
68t = 60t + 15
68t - 60t = 15
8t = 15
t = 15/8
t = 1.875 hrs which is: 1 + .875(60) = 1 hr 52.5 min