Please have explanations next to the steps. Thanks! Also, the answer is not -5. I went over it with my teacher and 16 mph should not become -16mph.

Please have explanations next to the steps. Thanks! Also, the answer is not -5.6. I went over it with my teacher and 16 mph should not become -16mph.

A ship A is 32 miles north of ship b and is sailing due south at 16 mph. Ship B is sailing due east at 12 mph. At what rate is the distance between them changing after 1 hour has passed?