SOLUTION: Two cars start from towns 840 miles apart and travel toward each other. They meet after 7 hours. Find the speed of each car if one travels 10mph faster than the other.

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Question 453484: Two cars start from towns 840 miles apart and travel toward each other. They meet after 7 hours. Find the speed of each car if one travels 10mph faster than the other.
Answer by pedjajov(51) About Me  (Show Source):
You can put this solution on YOUR website!
Each car travels r*t miles where:
r - speed of the car
t - time it travels
:
If first car travels with speed r, then the other one travels with speed r+10.
:
After 7 hours first car travels 7r miles, while other one travels 7(r+10) miles.
Together they travel 840 miles.
:
7r+7(r+10)=840, divide by 7
r+r+10=840, combine like terms
2r+10=120, subtract 10
2r=110, divide by 2
r=55
:
First car travels with speed of 55 mph, while the other one travels 65mph.