यदि किसी विशेष कूट (कोड) में 64 को 343 के रूप में लिखा गया है और 216 को 729 के रूप में लिखा गया है, तो उस कूट में 512 को किस रूप में लिखा जाएगा ?
Read this question in English
In a certain code if 64 is written as 343 and 216 is written as 729, then how is 512 written in that code?
(a) 1000 · (b) 1331 · (c) 1728 · (d) 2197
उत्तर और व्याख्या · explanation in English
Answer: (b) 1331
Both examples turn a cube n³ into (n + 3)³: 4³ becomes 7³ and 6³ becomes 9³. So 512 = 8³ becomes 11³ = 1331.
- 64 = 4³ and 343 = 7³; 216 = 6³ and 729 = 9³.
- The rule: n³ is written as (n + 3)³.
- 512 = 8³, so it is written as 11³ = 1331.
Remember · Recognise squares and cubes at sight (up to 20² and 12³); number codes often shift the base.
Question and answer: UPSC's official GS Paper II (2025, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·