An escalator moves towards the top level at the rate of 11 ft.sec and its length is 140 feet. If a person walks on the moving escalator at the rate of 3 feet per second towards the top level, how much time does he take to cover the entire length.	Choose the correct choice from the following choices:  A) 14 sec  B) 10 sec  C) 12 sec  D) 8 sec  E) 5 sec
Explanation :   Time taken to cover the entire length = tot.dist/resultant speed = 140/ (11+3)= 
<gadget id="calculator">140/ (11+3)</gadget>
<output>10</output>
10sec   Answer : 10 sec
<result>B</result>
An escalator moves towards the top level at the rate of 11 ft.sec and its length is 140 feet. If a person walks on the moving escalator at the rate of 3 feet per second towards the top level, how much time does he take to cover the entire length.