An escalator is descending at constant speed. A walks down and takes 50 steps to reach the bottom. B runs down and takes 90 steps in the same time as A takes 10 steps. How many steps are visible when the escalator is not operating?	Choose one
A) 80
B) 90
C) 100
D) 110
E) 120
Lets suppose that A walks down 1 step / min and   escalator moves n steps/ min   It is given that A takes 50 steps to reach the bottom   In the same time escalator would have covered 50n steps   So total steps on escalator is 50+50n.   Again it is given that B takes 90 steps to reach the bottom and time   taken by him for this is equal to time taken by A to cover 10 steps i.e   10 minutes. So in this 10 min escalator would have covered 10n steps.   So total steps on escalatro is 90 + 10n   Again equating 50 + 50n = 90 +10n we get n = 1   Hence total no. of steps on escalator is 100.   ANSWER:100
<result>C</result>
An escalator is descending at constant speed. A walks down and takes 50 steps to reach the bottom. B runs down and takes 90 steps in the same time as A takes 10 steps. How many steps are visible when the escalator is not operating?