I think there is a mistake in ur question....let me prove it...
let us say the escalater moves x steps per second then
9+42.5x = 17 +20x
=> 22.5x = 8
=> x =16/45
No of steps in the escalator is 9 + 85 *16/45 *2
which is not a integer.
nway this is the simplest way to solve this kind of problem
