There are two planes headed towards each other. One plane is traveling at 15 kilometers per minute, and the other is traveling at 10 kilometers per minute. Assuming that the planes are exactly 1000 kilometers apart, what distance will be between them one minute before they meet?
25 kilometers. The planes are traveling at a combined speed of 25 kilometers per minute. So they will be 25 kilometers apart one minute before they meet.
The initial distance between the planes is irrelevant.