Mph and time? (pre-calc.)

A truck enters a highway driving 60 mph. A car enters the highway at the same place 6 minutes later and drives 70 mph in the same direction. From the time the car enters the highway, how long will it take the car to pass the truck?

The car will pass the truck in how many minutes?

The car and truck will have traveled the same distance when the car passes the truck. Measuring the time from the moment the car enters the highway:

60(t+6) = 70t
10t = 360
t = 36

The car will pass the truck 36 minutes after the car enters the highway (42 minutes after the truck enters the highway).

At that time, both the car and the truck will be 42 miles from the place they entered the highway

when the car enters the highway, the truck has already made 6 miles ( 60 m.p.h. in 6 minutes).

Since the car is going 10 m.p.h. faster than the truck, ( 1 mile every 6 minutes), it will take 36 minutes (6miles * 6 minutes).

x = # of hours

60(x + 0.1) = 70x

60x + 6 = 70x

6 = 10x

x = 0.6

So it's 0.6 hours, which 36 minutes.

I hope this information was very helpful.

Truck is 6 miles ahead
Closing speed = 10 mph
Time = 6/10 hours = 36 minutes