A person walks 10m towards East. He then takes a right turn and walks 10m. He then takes a left turn and walks 10m. He then takes a left turn and walks 10m. What is the minimum distance between his starting and final point?
Correct: B
Let the starting point be the origin (0,0).
1. Walks 10m towards East: Position becomes (10, 0).
2. Takes a right turn (South) and walks 10m: Position becomes (10, 0-10) = (10, -10).
3. Takes a left turn (East) and walks 10m: Position becomes (10+10, -10) = (20, -10).
4. Takes a left turn (North) and walks 10m: Position becomes (20, -10+10) = (20, 0).
The final position is (20, 0) relative to the starting point (0,0).
The horizontal displacement is 20m East, and the vertical displacement is 0m.
Therefore, the minimum distance between his starting and final point is 20 meters.