A circular rim 28 inches in diameter rotates the same number of inches per second as a circular rim 35 inches in diameter. If the smaller rim makes x revolutions per second, how many revolutions per minute does the larger rim make in terms of x?
48π/x
75x
48x
24x
x/75
一个per second,一个per minute
题干意思:小圈直径28,大圈直径35,这里是4:5。两个圈每秒转的周长一样。设大圈每秒转动的圈数为y
2π*14*x=2π*17.5*y
题目求1 min
则60y=(4X/5)*60=48X