I really do not understand this question...what kind of formula can I use, because there is no displacement/distance? any help? What do I do since there is only one variable? thanks in advance. QUESTION: A shopper can ride up a moving escalator in 15 s. When the escalator is turned off, the shopper can walk up the stationary escalator in 8 s. a) How long would it take the shopper to walk up the moving escalator? b) Could the shopper walk down the moving escalator to the floor below? if so how long would it take?