Mithun walks 1 km towards the east, then turns south and walks 5 km. He again turns east and walks 2 km. After that, he turns north and walks 9 km. How far is he now from his starting point?

Appeared in: JSSH Staff Nurse - 2019

Explanation

The question asks for the shortest straight-line distance from the start to the end point, which is known as displacement.
To find this, we first calculate the net movement on the horizontal (East-West) axis and the vertical (North-South) axis.
Net Eastward movement = 1 km + 2 km = 3 km.
Net Northward movement = 9 km (North) - 5 km (South) = 4 km.
These two net movements form the perpendicular sides of a right-angled triangle.
The Pythagorean theorem (a² + b² = c²) is used to find the hypotenuse (the displacement). The calculation is √(3² + 4²) = √(9 + 16) = √25, which equals 5 km.

Option A: This value is an incorrect calculation. It may arise from errors in squaring the numbers or finding the square root.
Option C: This value represents only the net vertical displacement (4 km North). It does not account for the horizontal displacement.
Option D: This is an incorrect calculation. It does not correspond to the Pythagorean theorem or any simple sum of the distances.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Calculating displacement using the Pythagorean theorem in a directional reasoning problem as background academic context rather than a clinical decision trigger.
While not a clinical question, the logical reasoning and spatial awareness skills tested are essential for nurses.
These skills are applied daily when navigating large hospital facilities, responding to emergencies, or organizing patient care workflows efficiently.
Developing strong analytical abilities helps in interpreting complex patient charts, lab results, and monitoring data to make sound clinical judgments.

How to Approach the Question

First, carefully read the problem and break down the movement into individual steps, noting the direction and distance for each.
Visualize the path on a simple North-East-South-West coordinate system or sketch it on paper.
Calculate the total displacement along the horizontal (East-West) axis and the total displacement along the vertical (North-South) axis. Remember that movements in opposite directions cancel each other out.
Recognize that the net horizontal and vertical displacements are the two perpendicular sides of a right-angled triangle.
Apply the Pythagorean theorem (a² + b² = c²) to calculate the length of the hypotenuse, which represents the shortest distance from the start to the end point.
Select the option that matches your calculated result.

Concept Tested & Keywords

Concept Tested: Calculating displacement using the Pythagorean theorem in a directional reasoning problem.
Stem keywords: walks, east, south, north, far, starting point
Lead-in keywords: How far

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Practise the full JSSH Staff Nurse - 2019

Attempt every question from this paper in a timed mock, then review the full solution for each one.