B moves by taking 3 steps forward and 1 step backward (each step in one second )
He walks up a stationary escalator in 118 sec.
However on moving escalator he takes 40 sec to reach top .Find speed of escalator.

• In 4 secs he moves 2 steps forward.
  so in 118 sec i.e 29*4 + 2 sec ----> it means 29*2 (= 58) forward steps +2 forward steps (Total= 58+2=60) steps to reach top.
  if escalator is moving he takes 40 secs means 10*4 secs => 10*2 steps =20 steps by B and remaining 40 steps will be covered by escalator in 40 secs
  Therefore speed of escalator is 40 steps/40 secs= 1 step/sec.
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