A person walks 12 km due north, then 15 km due east, after that 19 km due west and then 15 km due south. How far is he from the starting point?
Answer & explanation
Answer: (a) 5 km
The moves net to 3 km south (12 north, 15 south) and 4 km west (15 east, 19 west) of the start. The straight-line distance is √(3² + 4²) = 5 km.
- North–south: 12 km north, then 15 km south → 3 km south.
- East–west: 15 km east, then 19 km west → 4 km west.
- Distance = √(3² + 4²) = √25 = 5 km.
Remember · Net out north–south and east–west moves separately, then apply Pythagoras once.
Question and answer: UPSC's official GS Paper II (2016, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·