SOLUTION: A truck enters a highway driving 60 mph. A car enters the highway at the same place 11 minutes later and drives 65 mph in the same direction. From the time the car enters the highw

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: A truck enters a highway driving 60 mph. A car enters the highway at the same place 11 minutes later and drives 65 mph in the same direction. From the time the car enters the highw      Log On


   



Question 712354: A truck enters a highway driving 60 mph. A car enters the highway at the same place 11 minutes later and drives 65 mph in the same direction. From the time the car enters the highway, how long will it take the car to pass the truck?
This is what I was able to do so far:
t = the number of minutes from when the car enters the highway until the car passes the truck
Convert minutes to hours: t minutes = t/60 hrs
Car: D =(speed of car)(time the car travels)
D = 65 * t/60
Truck: D = (speed of truck)(time the truck travels)
D = 60 * t+11/60
And this is where I got stuck:
65 * t/60 = 60 * t+11/60
t = ?????
I don't know where to start in order to solve for t. Your assistance will be appreciated!










Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Start a stopwatch when the car enters the highway.
The truck has a head start of
+60%2A%2811%2F60%29+=+11+ miles
Let +t+ = the time on the stop watch when
the car catches the truck
Let +d+ = the distance the car travels until
it catches the truck
-------------------------
The car's equation:
(1) +d+=+65t+
The truck's equation:
(2) +d+-+11+=+60t+
-------------------------
Substitute (1) into (2)
(2) +65t+-+11+=+60t+
(2) +5t+=+11+
(2) +t+=+11%2F5+
It will take the car +11%2F5+ hrs, or
+%2811%2F5%29%2A60+=+132+ min
+132+-+120+=+12+
2 hours and 12 minutes to pass the truck
---------------
check:
(1) +d+=+65%2A%2811%2F5%29+
(1) +d+=+143+
and
(2) +d+-+11+=+60%2A%2811%2F5%29+
(2) +d+-+11+=+132+
(2) +d+=+132+%2B+11+
(2) +d+=+143+
OK