Problem Solving

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?

48Ï€/x

75x

48x

24x

x/75

Hi! Try searching some of these questions before you ask them and you may see a couple of the same ones asked before. I will however, take a bite at this one:

Circumference of smaller rim = 28Ï€
Circumference of bigger rime = 35Ï€

If the smaller rim rotates x revolutions per second, then it means that it goes 28Ï€x inches/second. The problem tells us that the bigger rim must also go 28Ï€x inches/second which is the same thing as
(28Ï€x)/35Ï€ = 28x/35 = 4x/5 revolutions/second or (4x/5)(60) = 48x revs/min.

Choose C.