Hi All,
While this is an old post, it's a decent example of how the GMAT can test you on Geometry concepts using real-world items (and a story problem).
We're told that a fan blade is 10cm from the center of the fan (which means we have a radius of 10). We're then told that the fan blade spins for 15 seconds (which means that we're dealing with the circumference of a circle). We're asked how far the point "travels" if the fan makes 300 revolutions per minute.
The 'math' involved in this question can be done in a couple of different ways, but here's a step-by-step method that should be easy to follow:
Since radius = 10
Circumference = 2(pi)(R) = 2(pi)(10) = 20pi
So every revolution = 20pi cm traveled
15 seconds = 1/4 of a minute
(300 revolutions/minute)(1/4 of a minute) = 75 revolutions in 15 seconds
(20pi cm)(75) = 1500pi cm
Final Answer:
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Rich
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