An escalator is moving down. A person who comes down with normal speed, takes 50 steps to come down. Another person, who is slightly faster, takes 90 steps to come down. The time taken by the first person to move 10 steps is the same as the time taken by the second person to move 90 steps.
What is the total number of steps visible when the escalator is not moving ?
Note: The faster person takes more steps because, if you don't move at all, you take 0 steps and you come down, and your speed is still slower !