Answer
The speed of the first car :$58$ mph
Speed of the second car: $65$ mph
Work Step by Step
Let the speed of the first car be $x$
Speed of the second car be $y$
Total speed of the two cars $x+y$
One car is traveling $7$ mph faster than the other.
$y= x+7$ Equation $(1)$
Distance between the two cars after $4$ hours is $492$ miles.
$Speed = \frac{Distance}{Time}$
$x+y=\frac{492}{4}$
$x+y=123$
$x+x+7=123 $ From Equation $(1)$
$2x=123-7 $
$2x=116$
$x = 58$
Substituting $x$ value in Equation $(1)$
$y=x+7$
$y=58+7$
$y=65$
The speed of the first car :$58$ mph
Speed of the second car: $65$ mph
