Algebra
posted by Julia .
I can not figure out how to solve this problem:
"Two planes left the Chicago airport at the same time four hours ago. One is 40 miles per hour faster than the other one, and they are 6600 miles apart. What is the rate of each plane?"
I am not the best at distance problems like this. And it's an extra credit problem, which I really need. So can someone please help me?
I know it would be 6600=4r+40 or something...

speed 1 = r
speed 2 = (r+40)
assume opposite directions
6600 = 4 (r + 40) + 4 r
6600 = 4 r + 160 + 4r
8 r = 6440
r = 805
r+40 = 845