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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?
 

 Jan 24, 2021
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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

 Jan 24, 2021

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