Question

A truck enters a highway driving 60 mph. A car enters the highway at the same place 13 minutes later and drives 72 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 1

64.98 minutes or 1 hour and 5

Explanation:

When the car enters the highway, the truck has already traveled for 13 minutes, or 13/60 hours, at a speed of 60 mph. So the truck is ahead of the car by a distance of:

distance = speed x time

distance = 60 mph x 13/60 hours

distance = 13 miles

Now, the car is moving faster than the truck, so it will catch up to the truck. The relative speed of the car with respect to the truck is:

relative speed = car speed - truck speed

relative speed = 72 mph - 60 mph

relative speed = 12 mph

The time it will take for the car to catch up to the truck is:

time = distance / relative speed

time = 13 miles / 12 mph

time = 1.083 hours

Convert the time to minutes:

time = 1.083 hours x 60 minutes/hour

time = 64.98 minutes

So, it will take the car approximately 64.98 minutes or 1 hour and 5 minutes to pass the truck.