dunkin77 wrote:11. A point on the edge of a fan blade that is rotating in a plane is 10 centimeters from the center of the fan. What is the distance traveled, in centimeters, by this point in 15 seconds when the fan runs at the rate of 300 revolutions per minute ?
(A) 750π
(B) 1,500π
(C) 1,875π
(D) 3,000π
(E) 7,500π


The answer is B) - but for some reason my answer was A). Can you help?

In 60 seconds the fan rotates 300 times, so in 15 sec it will rotate
75 times.

Total distance covered = (perimeter of circle with radius as 10) * 75

= 2*pi*10 * 75
= 1500 * pi

Hence B

A point on the edge of a fan blade that is rotating in a plane is 10 centimeters from the center of the fan. What is the distance traveled, in centimeters, by this point in 15 seconds when the fan runs at the rate of 300 revolutions per minute ?
(A) 750π
(B) 1,500π
(C) 1,875π
(D) 3,000π
(E) 7,500π

300 revolutions / min = 300 * 15/60 = 75 revolutions in 15 seconds
Distance of the point from center = 10 cm (or radius = 10)
1 revolution = 2*pie*r = 20*pie
Thus 75 revolutions = 75*20*pie = 1500pie