An escalator moves towards the top level at the rate of 10 ft.sec and its length is 112 feet. If a person walks on the moving escalator at the rate of 4 feet per second towards the top level, how much time does he take to cover the entire length.  Answers
A) 14 sec
B) 10 sec
C) 12 sec
D) 8 sec
E) 9 sec

Rationale: "time taken to cover the entire length = tot . dist / resultant speed = 112 / ( 10 + 4 ) = 8 sec answer : d"
Answer: D