The digit in the unit place of the number 6¹²⁹ × 7³⁰⁷ is

Question

The digit in the unit place of the number 6¹²⁹ × 7³⁰⁷ is

1. A. 2
2. B. 4
3. C. 8 (Correct answer)
4. D. 6

Correct Answer

Option C — 8

Detailed Solution & Explanation

The correct answer is Option C (8).

Key Points

• Unit digit of 6¹²⁹ is always 6 (every power of 6 ends in 6).
• Unit digit of 7³⁰⁷: powers of 7 cycle 7, 9, 3, 1 with period 4; 307 mod 4 = 3, so it is the 3rd term = 3.
• Product's unit digit = unit digit of 6 × 3 = 18 → 8.

Additional Information

• Multiplying the two unit digits gives Option C.