2012 AMC 8 Problem 12
Attempt Problem 12 of the 2012 AMC 8 below, then check your answer against the video solution and professionally curated solution from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 2012 AMC 8 solutions, or check the answer key.
All problems are used with official legal permission of the Mathematical Association of America (MAA).
12.
What is the units digit of
Answer: A
Small hint:
Only the units digit of the base matters.
Big hint:
Powers of have a units-digit cycle of length .
Video solution:
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Written solution:
We have to find The following is true:
This means has the same units digit as so the units digit of is
Thus, the answer is A .
Problem 12 in other years
- 1985 AMC 8
- 1986 AMC 8
- 1987 AMC 8
- 1988 AMC 8
- 1989 AMC 8
- 1990 AMC 8
- 1991 AMC 8
- 1992 AMC 8
- 1993 AMC 8
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