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Mary and John have both completed a trip up an escalator. John took 15 steps on the way up and took 12 seconds to reach the top. Mary took only 7 steps and took 18 seconds to reach the top. How many steps does the escalator have in total?

 Sep 28, 2020
 #1
avatar+111144 
+1

Let the number of steps be x.

 

then John goes up   x-15   steps in 12 seconds

and Mary ....

 

 

You can finish it.

 Sep 28, 2020
 #2
avatar+27778 
+1

You can also solve for the RATE of the stairs, r

   then r * t    +   stairs taken = #stairs

 

John     15 + 12 r = #stairs

Mary       7 + 18r = # stairs

                  15 + 12r = 7+ 18r      now you can solve for r     

                                      then use r in either of the equations to calc #stairs

 Sep 28, 2020

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