A pulley whose diameter is 9 inches is connected by a belt to another pulley whose diameter is 6 inches. If the larger pulley runs at 1200 revolutions per minute, at how many revolutions per minute does the smaller pulley run?

Question

a. 800
b. 1080
c. 1600
d. 1800
e. 2000

please answer and explain

Answer 1

Since 9*2 = 6*3, the big pully turns 2 times while the small pulley turns 3 times
So, 3/2 * 1200 = 1800