Question

A wheel with a diameter of 3 feet makes a revolution every 2 minutes. How many feet will the wheel travel in 30 minutes?
(A) 3π
(B) 6π
(C) 45π
(D) 30π
(E) 15π

Answer 1

The diameter is 3 ft. So the radius is half that at 3/2 = 1.5 ft. The circumference (the distance around the wheel) is then C = 2pi*r = 2*pi*1.5 = 3pi feet. So one revolution (or complete 360 degree turn) will mean that the wheel has traveled 3pi feet. This one revolution occurs every 2 minutes. Since there are 30/2 = 15 two minute periods in 30 minutes, this means that the wheel has gone 15*3pi = 45 pi feet in 30 minutes. So the answer is C)

Answer 2

Circumference:
\[3\pi\]
\[15\times 3\pi=45\pi\]

Answer 3

thx