What is the speed of the walkway?

Question

Sam knows that he walks at a constant rate of 7 feet per second. While at the airport, he wishes to determine the speed of the moving sidewalk by first walking in the same direction as the walkway and then reversing direction. Walking on the moving sidewalk, Sam travels 190 feet forward in the same time it takes him to travel 90 feet in the opposite direction. What is the speed of the walkway?

Answer 1

 

With the moving sidewalk:

190 ft = (7+s)* T --->  190/(7+s) = t

 

Against hte moving sidewalk:

90 ft = (7-s)*T

 

 

90 = (7-s)*190/(7+s)

 

90(7+s) = 190(7-s)

 

630 +90x = 1330 - 190s

 

630 + 90s + 190s = 1330

 

280s = 1330 - 630

 

280s = 700

 

s = 700/280 = 70/28 = 35/14 = 5/2

 

5/2 = 2.5 = 2 and 1/2 feet per second