Question

If we represent the distance above the ground by a positive rational number and that
below the ground by a negative rational number, then answer the following question:
An elevator descends into a mine shaft at the rate of 4 metre per minute. If it begins
to descend from 7
metre above the ground, what will be its position after 18 minutes
from the ground?​

Answer 1

Since, the elevator going down, so the distance covered by it will be represented by a negative integer.

Change in position of elevator in one minute = −5 m.

Position of the elevator after 60 minutes = (−5)×60=−300 m

That means the position of the elevator will be 300 m below ground level.