What is the total number of digits printed, if a book containing 150 pages is to be numbered from 1 to 150?
Answer & explanation
Answer: (b) 342
Pages 1–9 use 9 digits, pages 10–99 use 90 × 2 = 180 digits, and pages 100–150 use 51 × 3 = 153 digits. The total is 342.
- Pages 1–9: 9 pages × 1 digit = 9.
- Pages 10–99: 90 pages × 2 digits = 180.
- Pages 100–150: 51 pages × 3 digits = 153.
- Total = 9 + 180 + 153 = 342.
Remember · Count digits band by band: pages in a band = last − first + 1, times the digits on each page.
Question and answer: UPSC's official GS Paper II (2017, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·