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.
375 m
420 m
14 sec
10 sec
Explanation:
Now we need to use the concept of relative velocity.
According to the question the person moves at the rate of 3 ft/s and 11ft/s which will be 14 ft/s
Length of the level is 140 ft
So speed = distance / time
Or time taken = distance / speed
= 140 / 14
= 10 secs
So the time taken to cover the entire length will be 10 secs.
Now we need to use the concept of relative velocity.
According to the question the person moves at the rate of 3 ft/s and 11ft/s which will be 14 ft/s
Length of the level is 140 ft
So speed = distance / time
Or time taken = distance / speed
= 140 / 14
= 10 secs
So the time taken to cover the entire length will be 10 secs.