se the formula distancerate X time and systems of linear equ

se the formula distance=rate X time and systems of linear equations to solve the following:
Two cars leave Pittsburgh at the same time, one traveling north and the other south. After 3 hours they are 297 miles apart. If one car is traveling 5 mph faster than the other, what is the speed of each?

Solution

Going in opposite directions their speeds are added.
The sum of the speeds is 297/3 = 99 mph
r + (r+5) = 99
2r = 94
r = 47 = speed of one car
52 mph = speed of other car