Question. Tom's rabbit can run at 25 miles per hour. His cat can run 20 miles per hour. The cat gets a 15-minute head start. In hours, how long will it take for the rabbit to catch up?
Answer. 1
What step-by-step reasoning justifies that answer?
Reasoning: The cat got a 15 / 60 = .25 hour head start. That means it ran 20 * .25 = 5 miles. The rabbit goes 25 - 20 = 5 mph faster than the cat. So it takes 5 / 5 = 1 hour for the rabbit to catch up.