A round archery target of diameter 1 m is marked with four scoring regions from the centre outwards as red, blue, yellow and white. The radius of the red band is 0.20 m. The width of all the remaining bands is equal. If archers throw arrows towards the target, what is the probability that the arrows fall in the red region of the archery target?
Answer & explanation
Answer: (c) 0.16
Taking every point of the target as equally likely, the probability is the red area over the whole area: (0.20 ÷ 0.50)² = 0.16. The widths of the other bands do not matter.
- Target radius = 1 m ÷ 2 = 0.50 m; red radius = 0.20 m.
- Probability = red area ÷ target area = (0.20/0.50)² = 0.4² = 0.16.
Remember · For circles, the ratio of areas is the square of the ratio of radii.
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). ·