An elevator descends into a mine shaft at the rate of 6 m/min. If the descend starts from 20 meter above the ground level, how long will it take to reach - 340m?
60 minutes. Take how far it is above ground (20 m) and add it to the absolute value of how far it is below ground (340 m) to get 360 meters, which you divide by the rate of descent (6 m/min) to get 60 minutes.
