A circular rim 20 inches in diameter rotates the same number of inches per second as a circular rim 15 inches in diameter. If the smaller rim makes x revolutions per second, how many revolutions per minute does the larger rim makes in terms of x ?  Pick.
A) 48pi/x  B) 75x  C) 48x  D) 80x  E) x/75
Revolutions - circumference of the rim.   =&gt; 20pi*X*60 = 15pi*Revolutions   =&gt; 4/3 *X *60 = Revolutions =&gt; 80X - Option 80x
<result>D</result>
A circular rim 20 inches in diameter rotates the same number of inches per second as a circular rim 15 inches in diameter. If the smaller rim makes x revolutions per second, how many revolutions per minute does the larger rim makes in terms of x ?