Einstein walks on an escalator at a rate of 5steps per second and reaches the other end in 10 sec. while coming back, walking at the same speed he reaches the starting point in 40secs. What is the number of steps on the escalator?  Choose the correct choice from the following: A) 40 B) 60 C) 120 D) 80 E) data insufficient
Let the speed of escaltor be X steps per sec.   And length of escalator be Y.   Einstein's speed = 5 step/ sec   Then,   During upward movement   5-X=Y/10   During downward movement   5+X=Y/40   By solving equations we get Y=80.   ANSWER:80
<result>D</result>
Einstein walks on an escalator at a rate of 5steps per second and reaches the other end in 10 sec. while coming back, walking at the same speed he reaches the starting point in 40secs. What is the number of steps on the escalator?