To save energy, the speed of the airport moving walkway was slowed down by 10% and as a result it takes an extra 7 seconds for it to complete the “trip”. How long, inseconds, does it take to complete the trip after the slow down?
x = normal rate
.9x = reduced by 10% rate
d = distance
d/x +7 = d/(.9x)
7 = d/(.9x) - d/x
7 (x)(.9x) = dx - .9dx
6.3 x2 = .1 dx
6.3 x = .1d note that d/x = time
d/x = 6.3/.1 = 63 seconds
after the slowdown 63 + 7 = 70 seconds
+328 
