A man is facing east. He turns 100° in the clockwise direction and then turns 145° in the anti-clockwise direction. Which direction is he facing now?

Appeared in: NHM UP Staff Nurse - 2019

Explanation

The problem requires calculating the net angular displacement from a starting direction.
A clockwise turn of 100° is followed by an anti-clockwise turn of 145°.
The net movement is calculated by subtracting the smaller turn from the larger one: 145° (anti-clockwise) - 100° (clockwise) = 45° in the anti-clockwise direction.
Starting from the East, a 45° turn towards the North (which is an anti-clockwise movement) results in the North-East direction.

Option A: This would be the final direction only if the net rotation was 0° or 360°, meaning the clockwise and anti-clockwise turns were equal in magnitude.
Option C: To face North from an initial position of East, a 90° anti-clockwise turn is required. The net turn in this problem is only 45°.
Option D: The South-West direction is 225° clockwise or 135° anti-clockwise from East. The net turn of 45° anti-clockwise is not sufficient to reach this direction.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Directional Sense and Rotation as background academic context rather than a clinical decision trigger.
Logical reasoning and spatial awareness are fundamental cognitive skills tested in the aptitude sections of nursing entrance examinations.
This type of question assesses the ability to process sequential instructions and visualize spatial relationships, a skill useful in navigating complex hospital layouts or following multi-step procedures.
What if? If the second turn was 100° anti-clockwise, the net turn would be 100° clockwise - 100° anti-clockwise = 0°. The man would end up facing his original direction, East.

How to Approach the Question

First, identify the initial direction of the person, which is East.
Next, list the sequence of turns, noting the direction (clockwise or anti-clockwise) and the angle for each.
Calculate the net rotation. Treat turns in opposite directions as having opposite signs. For instance, consider anti-clockwise as positive (+) and clockwise as negative (-). The net turn is the sum: (+145°) + (-100°) = +45°.
A positive result of 45° indicates a net turn of 45° in the anti-clockwise direction.
Apply this net rotation to the initial direction. A 45° anti-clockwise turn from East points directly to North-East.
Visualize a compass to confirm the final direction. If East is at 0°, North is at 90° (anti-clockwise). A 45° turn from East towards North is North-East.

Concept Tested & Keywords

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