SOLUTION: Use 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.

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Question 214383: Use 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?

Found 2 solutions by Alan3354, josmiceli:
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
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?
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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

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
When 2 things are moving opposite each other at constant speeds, you can
treat it as 1 thing moving at their combined speeds.
given:
t+=+3 hrs
d+=+297 mi
Let the combined speeds = r+%2B+r+%2B+5+=+2r+%2B+5
By expressing the combined speeds this way, I can
easily separate them later.
297+=+%282r+%2B+5%29%2A3
297+=+6r+%2B+15
6r+=+282
r+=+47
r+%2B+5+=+52
One car's speed is 47 mi/hr and
the other's speed is 52 mi/hr
check:
2r+%2B+5+=+99
297+=+99%2A3
297+=+297
OK