Two sisters go up 40-step escalators. The older sister rides the up escalator, but can only take 12 steps up during the ride since it is quite crowded. The younger sister runs up the empty down escalator, arriving at the top at the same time as her sister. How many steps does the younger sister take?
+36916 Sister on crowded side let the escolator carry her 40 - 12 = 28 steps
the other sister has to cover those 28 steps PLUS the original 40 steps = 68 steps
