SOLUTION: A child is running on a moving sidewalk in an airport. When he runs against the sidewalk's motion, he travels 77ft in 11 seconds. When he runs with the sidewalk's motion, h

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Question 1120737: A child is running on a moving sidewalk in an airport. When he runs against the sidewalk's motion, he travels
77ft
in
11
seconds. When he runs with the sidewalk's motion, he travels
225ft
in
15
seconds. What is the rate of the child on a still sidewalk and what is the rate of the moving sidewalk?

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let r = child’s rate on still sidewalk
Let s = rate of the moving sidewalk
————————————————————-
(1) +r+-+s+=+77%2F11+
(2) +r+%2B+s+=+225%2F15+
————————————-
(1) +r+-+s+=+7+
(2) +r+%2B+s+=+15+
——————————-
Add the equations
+2r+=+22+
+r+=+11+
And
(1) +11+%2B+s+=+15+
(1) +s+=+4+
———————————
Rate of child on still sidewalk
11 ft/sec
Rate of moving sidewalk
4 ft/sec