Question 1007829
Call the child's normal rate, r.
Call the rate of the walkway, w.
(r + w)(13) = 195
(r - w)(13) = 91
and
13r + 13w = 195
13r - 13w = 91
Now add these and get
26r = 286
r = 11 ft/s
By plugging in we find
w = 4 ft/s