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julial838
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catching up on a circle

by julial838 Wed May 13, 2015 12:01 pm

Here is the problem:
Two racecar drivers, A and B, are driving around a circular track. If A is 200 meters behind B and both drivers drive their respective constant rates, how long, in second, will it take for A to catch up to B?
The circumference of the racetrack is 1,400 meters.
B is driving 25 meters per minute faster than A.

Given answer is (B)

My questions:
1. B is faster than A, how can A catch up to B? Shouldn't it be B to catch up to A?
2. Then, if B is catching up A on a circular track, the difference between them is not 200 meters, but (the circumference - 200) meters, right? Thus my asnwer is actually (C)!
RonPurewal
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Re: catching up on a circle

by RonPurewal Thu May 14, 2015 9:17 pm

hi,
please read the forum rules before posting: we need a COMPLETE citation of the problem, exactly as originally presented -- including all answer choices.

this is something we need in general, but its importance should be particularly clear here. (you've stated that "the answer is B", but, right now, there's no way of knowing what "B" even is!)
RonPurewal
Students
 
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Re: catching up on a circle

by RonPurewal Thu May 14, 2015 9:17 pm

also, please note that there is one folder for CAT problems, and another for all other MPrep material. since you haven't named the source of this question, it seems likely that the question is from our CATs.
if that's the case, this post is in the wrong folder. so, in case that's indeed true, i'm going to lock this thread.

please re-post your query...
... with a complete transcription of the problem (with ALL answer choices, along with any part(s) of the answer key that you are quoting);
... in the correct folder.

thanks!