Brain Teaser #54
Up the Escalator
Ronnie takes the underground train to work and uses an escalator at the railway station.
If Ronnie runs up 7 steps of the escalator, then it takes him 27.0 seconds to reach the top of the escalator.
If he runs up 13 steps of the escalator, then it takes him only 18.0 seconds to reach the top.
How many seconds would it take Ronnie to reach the top if he did not run up any steps of the escalator at all?
