UPSC CSE 2024 · PYQ · Number System / Digit Counting · medium
What is the number of fives used in numbering a 260-page book?
- A.55
- B.56✓ Correct
- C.57
- D.60
Count occurrences of digit 5 in numbers 1 to 260. Units place: 5,15,25,...,255 → 26 occurrences. Tens place: 50-59 (10), 150-159 (10), 250-259 (10) → 30 occurrences. Hundreds place: 500-599 → 0 (since book has only 260 pages). Total = 26 + 30 + 0 = 56. Hence 56 fives are used.
💡
Practice unlimited UPSC CSE PYQs + AI-tracked progress on each topic.
Sign up free →Want more UPSC CSE practice?
Free daily 10-Q quiz · adaptive mocks · 4,000+ verified PYQs · AI doubt solver in Hindi + English