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1. A circular wheel 28 inches in diameter rotates (moves) the same number of inches per second as a circular wheel 35 inches in diameter. If the smaller wheel makes x revolutions per second, how many revolutions per minute does the larger wheel make in terms of x?
- A. 12x
- B. 12x
- C. 12x
- D. 12x
Answer: Option B
Explanation:
Let the revolutions made by larger wheel per minute be R.
Circumference of smaller wheel, 2 π r = 2 x π x (28/2) = 28π
Circumference of larger wheel, 2 π r = 2 x π x (35/2) = 35π
Speed of smaller wheel per minute = 60x
Distance covered by larger wheel per minute = Distance covered by smaller wheel per minute
or, R x 35π = 28π x 60x
or, R = 28π x 60x / 35π = 48x
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