Number System · Question 10 · Medium
What is the unit digit of 3^65 × 6^59 × 7^71?
- 2
- 6
- 8
- 4
Answer and explanation
Answer: D. 4
Explanation: 3^65 ends in 3 (65 = 4k + 1), 6^59 ends in 6, and 7^71 ends in 3 (71 = 4k + 3). 3 × 6 × 3 = 54, so the unit digit is 4.
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