सभी द्वि-अंकीय धनात्मक पूर्णांकों में 5 कितनी बार आता है?
Read this question in English
How many times does 5 appear in all two-digit positive integers?
(a) 18 · (b) 19 · (c) 20 · (d) 21
उत्तर और व्याख्या · explanation in English
Answer: (b) 19
5 is the tens digit in 50–59 (10 times) and the units digit in 15, 25, …, 95 (9 times). Counting appearances, 55 contributes two, and the total is 19.
- Tens place: 50, 51, …, 59 → 10 appearances.
- Units place: 15, 25, 35, 45, 55, 65, 75, 85, 95 → 9 appearances.
- Total = 10 + 9 = 19.
Remember · Count digit appearances place by place (tens, then units); a number like 55 is counted once in each place.
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). ·