A person goes 20 metres towards South, then turns left and goes 20 metres. He…

Concept: In a direction-sense problem, track the direction the person faces after each turn using a fixed rule: a LEFT turn rotates the facing 90 degrees anticlockwise and a RIGHT turn rotates it 90 degrees clockwise, cycling through North, West, South, East (anticlockwise) or North, East, South, West (clockwise). The final direction of travel is simply the facing direction during the last leg of the walk; the distances covered at each stage do not change it.

Application:

1. The person starts facing South and walks 20 m.

2. A left turn from South rotates the facing anticlockwise to East, so the person walks the next 20 m facing East.

3. A left turn from East rotates the facing anticlockwise to North, so the person walks the next 20 m facing North.

4. A right turn from North rotates the facing clockwise to East, so the final 60 m leg is walked facing East.

Plotting the path, South, then East, then North, then East, on a compass grid:

Cross-check: Re-applying the turn rule to each leg in order, left, left, right, independently reproduces the same final facing, confirming the result regardless of the distances walked at each stage.

Hence, the person is finally moving towards East.