speeddistancetime
posted by jen .
Please help me with this problem.
Two cars started from the same point and traveled on a straight course in
opposite directions for exactly 2 hours, at which time they were 208 miles
apart. If one car traveled, on average, 8 miles per hour faster than the other
car, what was the average speed for each car for the 2hour trip?
Thank you.

Never mind. I figured it out. :)
But now I am stuck with this one. Please help!
A group can charter a particular aircraft at a fixed total cost. If 36 people
charter the aircraft rather than 40 people, then the cost per person is greater by
$12. What is the cost per person if 40 people charter the aircraft?
Thanks. 
How about simply...
40x = 36(x+12)