Question

Suppose we represent the distance above the ground by a positive integer and that below the ground by a negative integer, then answer the following:
An elevator descends into a mine shaft at the rate of $5\text{m/min}$. What will be its position after one hour?

• A. None of these
• B. $250$
• C. $100$
• D. $200$

Answer 1

Answer: (A)

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 $=$ $-5\text{m}$

Position of the elevator after $60$ minutes $=$ $(-5)\times 60$

$=-300\text{m}$

That means the position of the elevator will be $300\text{m}$ below ground level.