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

An elevator descends into a mine-shaft at the rate of 6 m/min. If the elevator starts from 10 m above the ground level the time it will take to reach -350 m is

- 45 minutes
- 1 hours 30 minutes
- 1 hours
- 1 hours 15 minutes

**Answer: (3) 1 hour**

**Explanation:-**

The speed of an elevator = 6 m/min

The total height covered by the elevator = 10 + 350

= 360 m

Then, time taken by the elevator to cover 360 m = 360/6

= 60 min

As we know that 1 hr. = 60 min

Then, the elevator starts from 10 m above the ground level the time it will take to reach – 350 m is 1 hour.

Hence, the answer is (3) 1 hour.