A man drives 40 kms to North and then turning East, he drives 50 kms. Again, he turns to his right and drives 30 kms. Once again, he turns to his right and drives 50 kms. How far is he from his starting place?

Appeared in: RRB Staff Nurse Jaipur-6th June 2018

Explanation

The problem requires calculating the net displacement from a starting point after a series of movements.
The eastward movement of 50 km is completely cancelled out by the westward movement of 50 km.
The net movement is determined by the difference between the northward and southward travel.
The man travels 40 km North and then 30 km South.
The final displacement is 40 km (North) - 30 km (South) = 10 km in the North direction from the starting point.

Option A: This value (80 kms) might be obtained by incorrectly adding the first and second distances (40 + 50 = 90) or the second and third (50 + 30 = 80). It does not represent the final displacement from the origin.
Option B: This is the distance of the eastward and westward legs of the journey. While it's a value present in the problem, it represents a cancelled-out movement and not the final distance from the starting point.
Option C: This value is a result of incorrect calculation. There is no logical combination of the given movements that results in a 20 km displacement.

Visual 1: Diagram: A visual path on a 2D grid showing the four movements. The path starts at an origin, goes up 4 units, right 5 units, down 3 units, and left 5 units, clearly ending 1 unit directly above the origin. This helps visualize how the East-West paths cancel out.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Direction and Distance as background academic context rather than a clinical decision trigger.
This type of question assesses logical and spatial reasoning skills, which are essential for problem-solving in any field.
The core skill is breaking down a complex problem into simpler, perpendicular components (North-South vs. East-West) and solving for each.
This methodical approach is similar to how a nurse might triage multiple patient needs by categorizing them by urgency and type.

How to Approach the Question

First, identify the starting point and treat it as the origin (0,0) on a coordinate plane.
Read each step of the journey and translate the direction and distance into a change in coordinates. North is positive Y, East is positive X, South is negative Y, and West is negative X.
Keep a running total of the coordinates after each move.
Alternatively, sum all North-South movements and all East-West movements separately.
Calculate the net displacement: Total North - Total South, and Total East - Total West.
The final distance is the straight line from the origin to the final point. If there is displacement on only one axis (like here), that is the answer. If on both, use the Pythagorean theorem: distance = √(net X² + net Y²).

Concept Tested & Keywords

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Practise the full RRB Staff Nurse Jaipur-6th June 2018

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