SOLUTION: 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 hig

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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?
Found 2 solutions by vleith, ankor@dixie-net.com:
Answer by vleith(2983) (Show Source):
You can put this solution on YOUR website!
The truck had a 15 minutes head start and was going 60mph. That is a mile per minute. So 15 minutes later the car eters the road exactly 15 miles behind the truck.
The car is going 8mph faster than the truck. So how much time does it take to go 15 miles at 8 mph?

1.875 hours or 1:52 minutes 30 seconds

Answer by ankor@dixie-net.com(22740) (Show Source):
You can put this solution on YOUR website!
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