A circular rim 28 inches in diameter rotates the same number of inches per second as a circular rim 42 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 ?  Answers:  A) 40x  B) 75x  C) 48x  D) 24x  E) x/75
The larger rim must circulate for the same number of inches the smaller rim does.   C = (pi)d   C(small): (pi)*28   C(large): (pi)*42   Lets say the time horizon is 60 seconds, so during that time the smaller rim covers a distance of (pi)*28*60 = (pi)*(1680) inches   (pi)*(1680) = (pi)*(42)(x)   pi*(40) = pi*(x)   40=x   Answer: A. 40x
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A circular rim 28 inches in diameter rotates the same number of inches per second as a circular rim 42 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 ?