An elevator descends into a mine shaft at the rate of . If the descent starts from above the ground level, how long will it take to reach a depth of ?
Answer
The correct answer is — Calculate the time taken by dividing the total distance by the rate of descent: .
Step-by-step solution
- Determine the initial position of the elevator relative to ground level: .
- Determine the final position of the elevator: .
- Calculate the total distance to be descended: Total distance = Initial position - Final position = .
- Determine the rate of descent: .
- Calculate the time taken by dividing the total distance by the rate of descent: .
Common mistake: Students often calculate the distance as by ignoring the fact that descent starts above the ground level.
Concept tested: Subtraction and division of integers in context of height and depth
Published · How this solution was prepared and checked