Didn't think about the concept of relative speed. Didn't remember it, so I solved this in another way.
We know the length of the track is 12pi and we also know the average speed of both A and B.
So, in order for them to have ran a complete lap, the (average speed * time) / length of the track (as in, total distance) should be an integer, though naturally not the same for both of them.
The lowest number in the options provided is 6 hours, hence D is our answer.
We know the length of the track is 12pi and we also know the average speed of both A and B.
So, in order for them to have ran a complete lap, the (average speed * time) / length of the track (as in, total distance) should be an integer, though naturally not the same for both of them.
The lowest number in the options provided is 6 hours, hence D is our answer.
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