An elevator descends into a mine shaft at the rate of 6 m/min. If the descent starts at 10 m above ground level, how long will it take to reach -350m?

Given: An elevator descends into a mine shaft at the rate of 6 m/min.

The descent starts at 10 m above ground level

To find:  How long will it take to reach -350m

Solution:

Rate of the descent of the elevator = 6 meters/minute

Total distance of descent = $10 - ( -350) = 10 + 350 = 360$ m

So time taken to descend to $-350$ m depth = $\frac{360}{6}$ = 60 minutes or 1 hour

Required time taken = 60 minutes or 1 hour