A child is riding a tricycle along a straight horizontal road. The pedals are attached directly to the front wheel, which has a radius of 15 cm. The rear wheels are smaller and have a radius of 8 cm. There is no slip between the wheels and the road surface. If the child is pedaling at 16 rpm (revolutions per minute), then the angular speed of the rear wheels is closest to:

You have two photos of a person walking. one shows the person at the corner of third and main streets, the other shows the person at the corner of tenth and main streets. there are lampposts at every corner in this town, and the first picture shows it to be 10: 32: 00 exactly. the second picture shows it to be 10: 49: 30. you know three facts: (1) all of the clocks are synchronized; (2) there are exactly 12 equal-sized blocks per kilometer in this town; and (3) the streets that cross main in this area are numbered consecutively, with no interruptions. what is the person’s average speed in kilometers per hour?