SOLUTION: A truck enters a highway driving 60 mph. A car enters the highway at the same place 9 minutes later and drives 69 mph in the same direction. From the time the car enters the highwa

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Question 493783: A truck enters a highway driving 60 mph. A car enters the highway at the same place 9 minutes later and drives 69 mph in the same direction. From the time the car enters the highway, how long will it take the car to pass the truck?

Answer by nerdybill(7384) About Me  (Show Source):
You can put this solution on YOUR website!
A truck enters a highway driving 60 mph. A car enters the highway at the same place 9 minutes later and drives 69 mph in the same direction. From the time the car enters the highway, how long will it take the car to pass the truck?
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Apply the distance formula of d=rt
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Since speed is given in terms of "hours" we must convert 9 minutes to hours:
9 minutes = 9/60 hours = 3/20 hours
.
Let x = time (hours) it takes car to pass the truck
then
60(x + 3/20) = 69x
multiplying both sides by 20:
60(20x + 3) = 1380x
1200x + 180 = 1380x
180 = 180x
1 hour = x