Question

A 3-foot diameter wheel travels at a rate of 45 feet per second. How many seconds does it take for the wheel to make 100 turns?

Answer 1

since the circumference is 3π feet, it makes 45/3π = 15/π turns per second.

That is π/15 seconds per turn. So, it takes 100π/15 = 20π/3 seconds to do the job.