एक मेज़ का ऊपरी पृष्ठ (top of a table) आयताकार है और उसके आयाम 6′ × 10′ हैं। मेज़ के ऊपरी पृष्ठ के दो आयताकार भागों को नीले रंग से रंगा गया है; इन दोनों भागों के आयाम 2·5′ × 8′ हैं और उनमें से प्रत्येक की सटीक दो भुजाएँ, मेज़ के ऊपरी पृष्ठ के दो किनारों के उभयनिष्ठ हैं। यदि मेज़ को ज़मीन पर स्थिर रखा जाता है और मेज़ के ऊपरी पृष्ठ के शेष भाग को सफ़ेद रंग से रंगा जाता है, तो ऊपर से देखने पर कितने भिन्न प्रतिरूप (पैटर्न) संभव हैं?
Read this question in English
The top of a table is rectangular and its dimensions are 6′ × 10′. Two rectangular portions of the table top are painted in blue colour; both these portions have dimensions 2.5′ × 8′ and each of them has exactly two sides common with two edges of the table top. If the table is fixed to the ground and the remaining portion of the table top is painted in white, how many different patterns are possible when observed from above?
(a) 2 · (b) 4 · (c) 6 · (d) 8
उत्तर और व्याख्या · explanation in English
Answer: (b) 4
Each 2·5′ × 8′ strip must lie with its 8′ side along a 10′ edge and sit in a corner. Two strips cannot share the same 10′ edge without overlapping, so one strip goes to each long edge, at its left or right end: 2 × 2 = 4 patterns.
- The 8′ side cannot lie along the 6′ edge (8 > 6), so it lies along a 10′ edge and the 2·5′ side along a 6′ edge.
- Two sides common with two table edges means the strip sits in a corner (it cannot touch two opposite edges, since 2·5 < 6 and 8 < 10).
- Two strips along the same 10′ edge would overlap (8 + 8 > 10), so one strip lies along each 10′ edge; they do not meet since 2·5 + 2·5 = 5 < 6.
- Each strip can be at the left or the right end of its edge: 2 × 2 = 4.
- The table is fixed, so these four layouts (both left, both right, and the two diagonal ones) all look different from above.
Remember · Fix the orientation first (which side fits which edge), then count positions; a fixed table means mirror images count separately.
Question and answer: UPSC's provisional GS Paper II (2026, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·