[From Thinking Mathematically p. 65. Modified by Sam Rebelsky.]
Once while riding on my bicycle along a path, I crossed a strip of wet paint about six inches wide. After riding a short time in a straight line I looked back at the marks on the pavement left by the wet paint picked up on my tires. What did I see? In particular, did I see separate marks from the front and back tires? What else do you need to know to answer this question?