A truck enters a highway driving 60mph. A car enters the highway at the same place 10 minutes later and drives 69mph in the same direction. From the time the car enters the highway, how long will it take for the car to pass the truck?
The car will pass the truck in [___] minutes.
Remember that
the speed is equal to divide the distance by the time
s=d/t
d=s*t
when the car enter the highway--------> 10 min
so
distance of the truck is
60*(10/60)=10 miles
the equation of the distance at this moment is
y=60x+10
the equation of the distance of the car is
y=69x
equate both equations
69x=60x+10
69x-60x=10
9x=10
x=10/9 hours
convert to minutes
(10/9)*60=66.67 minutes
answer is
66.67 minutes