How many times does 5 appear in all two-digit positive integers?

Question

How many times does 5 appear in all two-digit positive integers?

1. A. 18
2. B. 19 (Correct answer)
3. C. 20
4. D. 21

Correct Answer

Option B — 19

Detailed Solution & Explanation

The correct answer is Option B (19).

Key Points

• Two-digit numbers run 10–99. The digit 5 in the units place: 15, 25, …, 95 → 9 times.
• The digit 5 in the tens place: 50, 51, …, 59 → 10 times.

Additional Information

• Total = 9 + 10 = 19 (55 is counted once in each place, correctly), giving Option B.