SOLUTION: Two people start driving toward each other on the same highway at the same time from towns 420 miles apart. One car travels 15 mph faster then the other. what is the rate of each o

Algebra ->  Coordinate Systems and Linear Equations -> SOLUTION: Two people start driving toward each other on the same highway at the same time from towns 420 miles apart. One car travels 15 mph faster then the other. what is the rate of each o      Log On


   

Question 188294: Two people start driving toward each other on the same highway at the same time from towns 420 miles apart. One car travels 15 mph faster then the other. what is the rate of each other if they meet in 4 hrs.

answer: The first car travels at 60 mph; the second car travels at 45 mph.
need a full break down of how my text book got this answer
Answer by jojo14344(1513) About Me  (Show Source):
You can put this solution on YOUR website!


Basic Eqn, Speed=Distance/Time

We get, Distance=Speed*Time

Since two cars travel on the same highway 420 miles apart, we need to add the Speed of each in 4 hours to cover the 420 miles.

Let S%5B1%5D=15%2Bx, and S%5B2%5D=x


Distance=S%5B1%5D%2AT%5B1%5D%2BS%5B2%5D%2AT%5B2%5D
420mi=%2815%2Bx%29%284%29%2Bx%284%29
420=60%2B4x%2B4x
420-60=8x
360=8x ------>cross%28360%2945%2Fcross%288%29=cross%288%29x%2Fcross%288%29
highlight%28x=45mph%29, Speed of Slower car
45%2B15=highlight%2860mph%29, Speed of Faster car

Thank you,
Jojo