A boy walks 20 m towards North, then turns left and walks 30 m. Then he turns left again and walks 20 m. How far is he from the starting point?

1. A

   50 m

2. B

   30 m

3. C

   20 m

4. D

   10 m

Appeared in: NORCET 2 - 2021 (shift-1)

Explanation

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• The problem involves calculating the net displacement after a series of movements.
• The first movement is 20 m North, and the third movement is 20 m South.
• Since these movements are equal in magnitude and opposite in direction, they cancel each other out in the North-South axis.
• The only remaining movement is the 30 m walk to the West.
• Therefore, the final distance from the starting point is exactly 30 m.

Why Other Options Were Wrong

• Option A: This is the sum of the first two distances (20 m + 30 m = 50 m). This would be incorrect as it represents the total path length after two movements, not the final displacement from the start.
• Option C: This value represents the distance of the first and third legs of the journey. It is not the final distance from the starting point.
• Option D: This value might result from an incorrect calculation, such as subtracting one distance from another (30 m - 20 m = 10 m). This does not correspond to the geometric path taken.

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Clinical Relevance

• Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain This question tests logical reasoning skills, specifically the ability to solve problems involving direction and distance as background academic context rather than a clinical decision trigger.
• While not a clinical question, this type of logical reasoning is a foundational skill for nurses.
• It helps in navigating complex hospital layouts, following multi-step procedures accurately, and making logical deductions in patient care scenarios.
• What if the second turn was a right turn instead of a left? The boy would walk 20m North, then 30m West, then 20m East. His final displacement would still be 30m West from the starting point, but his final position would be different.

How to Approach the Question

• First, carefully read the question and identify each distinct movement, including its direction and distance.
• It is helpful to draw a simple diagram to visualize the path. Use arrows to represent the direction of movement.
• Assume a starting point and plot each movement sequentially. A simple North-East-South-West compass rose can be used as a reference.
• Break down the movements into their North-South and East-West components.
• Calculate the net displacement in each direction. In this case, the North (+20m) and South (-20m) movements cancel out.
• The final distance from the start is the magnitude of the remaining net displacement.

Concept Tested & Keywords

• Concept Tested: This question tests logical reasoning skills, specifically the ability to solve problems involving direction and distance.
• Stem keywords: walks, North, left, far, starting point
• Lead-in keywords: How far

Question ID

QvqAXkUOocqBl2nB2YLzgg

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