Rana walks 20 metres straight towards the north. Then he walks 20 metres towards his right. After that, at each subsequent left turn, he walks 5 metres, 25 metres and 25 metres respectively. How far is he now from his starting point, measured in a straight line?

Introduction / Context:
This problem combines several turns and different distances in a direction sense setting. The question tests the candidate's ability to correctly interpret right and left turns and then to derive the net displacement from the starting point. Because the path involves repeated turning and returning towards the general area of the starting point, it is especially important to keep track of both horizontal and vertical components of the movement.

Given Data / Assumptions:

• Rana first walks 20 metres straight towards the north.
• Then he walks 20 metres towards his right, which is east when he is facing north.
• After that, he turns left and walks 5 metres.
• He turns left again and walks 25 metres.
• He turns left yet again and walks 25 metres.
• All turns are right angles.
• We need the straight line distance from the starting point to his final position.

Concept / Approach:
We will model the movement on a coordinate plane. Set the starting point at (0, 0). Let north be positive y, south negative y, east positive x and west negative x. As Rana walks and turns, we update his coordinates step by step. At the end, we use Pythagoras on the net horizontal and vertical changes to compute the shortest distance from the origin to the final point. In many such problems, because of symmetry and cancellation, the displacement becomes a simple integer.

Step-by-Step Solution:
Step 1: Start at (0, 0) facing north. Step 2: Rana walks 20 metres north to reach (0, 20). Step 3: Facing north, his right side is east. He walks 20 metres east, so his position becomes (20, 20). Step 4: Now he turns left from facing east, so he faces north and walks 5 metres, reaching (20, 25). Step 5: Turning left again from north means he now faces west. Walking 25 metres west takes him to (-5, 25). Step 6: Turning left again from west means he faces south. Walking 25 metres south brings him to (-5, 0). Step 7: The final coordinates are (-5, 0). Therefore he is 5 metres west of the starting point. Step 8: The straight line distance from (0, 0) to (-5, 0) is simply 5 metres.

Verification / Alternative check:
We can verify by net movement. Horizontally, Rana moves 20 metres east and later 25 metres west, giving a net 5 metres west. Vertically, he moves 20 metres north, then 5 metres north and finally 25 metres south. Net vertical movement = 20 + 5 minus 25 = 0 metres. Since the net vertical displacement is zero and the net horizontal displacement is 5 metres west, the shortest distance to the origin is 5 metres. This matches the coordinate based calculation exactly.

Why Other Options Are Wrong:

• Option B, 20 metres, could arise if someone incorrectly uses only the first leg and ignores subsequent cancellations.
• Option C, 25 metres, might be chosen by those who mistake the largest single segment for the final displacement.
• Option D, 30 metres, may come from adding or subtracting distances without taking direction into account properly.
• Option E, 10 metres, is another random distractor with no basis in the net displacement calculation.

Common Pitfalls:
A major source of confusion is interpreting left and right as absolute instead of relative to the current facing direction. For instance, left from east is north, not west. Another frequent mistake is forgetting that multiple legs can cancel out each other in net displacement, leading to overestimation of distance. Always distinguish clearly between total distance walked and straight line displacement from the starting point.

Final Answer:
Rana is now 5 metres away from his starting point, so the required distance is 5 metres.