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)      (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. 
 
  | 
 
  
 
 |   
 
 |