Brain Teasers
Moving Escalator
If it takes Mad Ade 2 minutes to walk up a moving escalator in the same direction as the escalator, but 6 minutes - at the very same pace - down the same escalator, how much faster than the escalator is Mad Ade walking.
Answer
Mad Ade is walking twice as fast as the escalatorMad Ade's average speed upwards is just the average speed of his walking (call this W) plus the average speed of the escalator (call this E); and his average speed down is just the average speed of his walking minus plus the average speed of the escalator.
So
Time to walk up 2(W + E) = time to walk down 6(W - E)
This reduces to W = 2E
or twice as fast as the escalator
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