Question 1110220
A child is running on a moving sidewalk in an airport.
 When she runs against the sidewalk's motion, she travels 50ft in 10 seconds.
 When she runs with the sidewalk's motion, she travels 91ft in 13 seconds.
 What is the rate of the child on a still sidewalk and what is the rate of the moving sidewalk?
let w = the walking speed of the child
let s = the moving sidewalk speed
Write an equation for each way
10(w-s) = 50
13(w+s) = 91
simplify both equation; divide 1st eq by 10, the 2nd eq by 13, we have
w - s = 5
w + s = 7
----------addition eliminates s, find w
2w = 12
w = 6 ft/sec on a still sidewalk
Find s
6 + s = 7
s = 1 ft/sec is speed of the moving sidewalk