An elevator descends into a mine shaft at the rate of 6 m/min. If the descent starts from 10 m above the ground level, how long will it take to reach −350m? [4 MARKS]

Calculations: 1 Mark
Steps: 2 Marks
Result: 1 Mark

Given that
An elevator descends into a mine shaft at the rate of 6 m/min.
The descent starts from 10m above the ground level.

Now, the distance descended is denoted by a negative integer.
Initial height = +10 m
Final depth = −350 m
Total distance to be descended by the elevator = (−350) − (+10) = −360 m
Time taken by the elevator to descend −6 m = 1 min
Thus, time taken by the elevator to descend −360 m = (−360) $÷$ (−6)
= 60 minutes = 1 hour

Hence it will take 1 hour to reach -350m.