Problem: mr . shah decided to walk down the escalator of a tube station . he found â that if he walks down 26 steps , he requires 30 seconds to reach the bottom . however , if he steps down 34 stairs he would only require 18 seconds to get to the bottom . if the time is measured from the moment the top step begins â to descend to the time he steps off the last step at the bottom , find out the height of the stair way in steps ?
Rationale: ( s 1 * t 2 ~ s 2 * t 1 ) / ( t 2 ~ t 1 ) = ( 26 * 18 ~ 34 * 30 ) / ( 18 ~ 30 ) = 46 answer : c
annotated_formula: add(26, multiply(divide(subtract(34, 26), subtract(30, 18)), 30))