A moving sidewalk in an airport moves people between gates. It takes Jason's \( 8 \) -year-old daughter Josie \( 10 \) sec to travel \( 50 \) ft walking with the sidewalk. It takes her \( 7 sec \) to walk \( 21 ft \) against the moving sidewalk (in the opposite direction). Find the speed of the sidewalk and find Josie's speed walking on non-moving ground.
Let x represent the speed of the side walk and y represent her walking speed
(x+y)10 = 50
(y-x) *7 = 21
y =4 ft/sec ; x = 1 ft/sec
so the speed of the sidewalk is 1 ft/sec. the speed of the Josie's speed walking is 4 ft/sec.