Escalators visible steps question.

We get an equation system like this from the information provided:

1) $N = t(V + E)$

2) $N = (t + 9 - 10)E + (t + 9)V = (t - 1)E + (t + 9)V$

Where N is number of steps, E is velocity of escalator (steps/second), V is velocity of person (steps/second) and t is time.

Then we get that $E = 9V$ from these equations. So if person takes $50$ steps normally to complete the distance, escalator moves $9 * 50 = 450$ steps by itself, so the answer is $50 + 450 = 500$ steps. :)