Physics
posted by Laura .
A person climbs from a Paris metro station to the street level by walking up a stalled escalator in 96.5 s. It takes 60.0 s to ride the same distance when standing on the escalator when it is operating normally. How long would it take for him to climb from the station to the street by walking up the moving escalator?

This is just like a work problem. Think of the distance traveled in 1 second.
1/96.5 + 1/60 = 1/37
so, walking while riding takes only 37 seconds