North then west — Direction Sense Aptitude Question
North then west: A woman cycles 3 km north and then 4 km west. How far is she from her starting point? Answer and worked solution on CodeKairo.
- Topic: Direction Sense
- Section: Logical Reasoning
- Difficulty: Easy
- Time target: 45 seconds
Question
A woman cycles 3 km north and then 4 km west. How far is she from her starting point?
Options
- 1 km
- 5 km
- 7 km
- 25 km
Show the answer and the worked solution
Correct answer: B. 5 km
Worked solution
- Displacement = √(3² + 4²) = √25 = 5 km.
Answer: 5 km.
The idea
The direction of each leg does not affect the distance, only the final bearing. Any two perpendicular legs of 3 and 4 give 5.
Shortcut. The gap lies strictly between 4 km (the longer leg) and 7 km (the sum of the legs), so 5 km is the only candidate.
Common trap. "25 km" — computing 3² + 4² = 25 and forgetting to take the square root.