An elevator decends into a mind shaft at the rate of 6 metre per minute. if the decent starts from 10 m above the ground level, how long will it take to reach -350 m?

 Distance descended is  denoted by a negative  integer.

Initial height is = 10 m

Final depth = -350 m

Total distance to be descended by the elevator is = 10 -(- 350 ) = 360 m

Time taken by the elevator to descend 6m = 1 m  

Thus, the time taken by the elevator to descend 360 m 

= 360 / 6 

= 60 minute 

= 1 hour