A dog spots a cat 50 feet away and starts to chase it. At the same moment, the cat starts to run away from the dog. The dog is running 12 feet per second and the cat is running 10 feet per second. Let t represent the time elapsed (in seconds) since the chase began. Let d represent the distance between the cat and the dog (in feet) Write a formula to define the distance between them (d) in terms of the time elapsed (t).