An escalator moves towards the top level at the rate of 15 ft.sec and its length is 200 feet. If a person walks on the moving escalator at the rate of 5 feet per second towards the top level, how much time does he take to cover the entire length.
Select:  A) 5sec  B) 10sec  C) 20sec  D) 15sec  E) 25sec
Explanation :   Time taken to cover the entire length = tot.dist/resultant speed = 200/ (15+5)= 
<gadget id="calculator">200/ (15+5)</gadget>
<output>10</output>
10sec   Answer : 10sec
<result>B</result>
An escalator moves towards the top level at the rate of 15 ft.sec and its length is 200 feet. If a person walks on the moving escalator at the rate of 5 feet per second towards the top level, how much time does he take to cover the entire length.