SOLUTION: a truck drives north at 60 mph, one-and-half hour later a car drives in the the same direction at 70 mph . for how many hours must the car drive for it to be 50 miles ahead of the

Question 811795: a truck drives north at 60 mph, one-and-half hour later a car drives in the the same direction at 70 mph . for how many hours must the car drive for it to be 50 miles ahead of the truck.
Found 2 solutions by richwmiller, josmiceli:
Answer by richwmiller(17219) (Show Source): You can put this solution on YOUR website!
In the hour and a half the truck has traveled 90 miles.
You want to get 50 ahead of the truck
That is a total of 140 miles 90+50=140
Thhe car travels ten miles faster than the truck
140/10=14 hours to get 50 miles ahead of the truck

Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
The truck's head start is mi
Let = the driving time for the car when
it is mi ahead of the truck
Let = the distance the car travels
when it meets the truck
------------------------------
Equation for truck:
(1)
Equation for car:
(2)
------------
By substitution:
(1)
(1)
(1)
------------
In 9 hrs they meet
From the place where they meet, let
the car go mi, and the
truck go
Let = the time to do this
truck's equation:
(1)
car's equation:
(2)
----------------
(1)
(1)
(1)

It takes 14 hrs for the car to get 50 mi ahead
of the truck

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