260 पृष्ठों की एक पुस्तक को संख्यांकित करने के लिए प्रयुक्त होने वाले अंक पाँच की संख्या कितनी है?
Read this question in English
What is the number of fives used in numbering a 260-page book?
(a) 55 · (b) 56 · (c) 57 · (d) 60
उत्तर और व्याख्या · explanation in English
Answer: (b) 56
Count the digit 5 place by place in 1 to 260. It appears 26 times in the units place and 30 times in the tens place (50–59, 150–159, 250–259), a total of 56.
- Units place: 5, 15, 25, …, 255, which is 26 numbers.
- Tens place: 50–59, 150–159 and 250–259, 10 each, 30 in all.
- Hundreds place: there is no page from 500 upwards, so 0.
- Total fives = 26 + 30 = 56.
- Check: 55, 155 and 255 each use two fives; they are counted once in the units count and once in the tens count, as they should be.
Remember · Count a digit place by place (units, tens, hundreds); numbers like 55 are then automatically counted twice.
Question and answer: UPSC's official GS Paper II (2024, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·