Robin takes the underground train to work and uses an escalator at the railway station. If Robin runs up 6 steps of the escalator, then it takes him 75.0 seconds to reach the top of the escalator. If he runs up 13 steps of the escalator, then it takes him only 57.5 seconds to reach the top. How many seconds would it take Robin to reach the top if he did not run up any steps of the escalator at all?   Hint Hint