An elevator descends into a mine shaft at the rate of 6 m/min. If the descendstarts from 20 meter above the ground level, how long will it take to reach - 340m?

It has to travel 20 meters before it gets to ground level, then another 340 meters till it reaches - 340 ... so it has to travel a total of 360 meters

and if it descends at a rate of 6 meters per minute ...

360/6 = 60 minutes ... or 1 hr to reach - 340 <==