Question

A bicycle with 18-in.-diameter wheels has its gears set so that the chain has a 6-in. radius on the front sprocket and 3-in. radius on the rear sprocket. The cyclist pedals at 195 rpm.
Find the linear speed of the bicycle in in/min (correct to at least two decimal places)

Answer 1

the gear ratio means that the wheel is turning twice as fast as the pedals.
2 * 190rev/min * 18π in/rev = 21488.49 in/min

over 3 rev per second? That's some fast pedaling. But only about 20 mi/hr, since the wheels are so small.