2015 AMC 8 Problem 12
Attempt Problem 12 of the 2015 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 2015 AMC 8 solutions, or check the answer key.
All problems are used with official legal permission of the Mathematical Association of America (MAA).
12.
How many pairs of parallel edges, such as and or and does a cube have?
Answer: C
Small hint:
Group cube edges by direction.
Big hint:
Each edge is parallel to three other edges, but pair-counting double counts.
Video solution:
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Written solution:
A cube has edges. For any edge, there are other edges parallel to it.
This counts each pair twice, once from each edge in the pair, so the number of pairs of parallel edges is
Thus, C is the correct answer.
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
- 1994 AMC 8
- 1995 AMC 8
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- 1997 AMC 8
- 1998 AMC 8
- 1999 AMC 8
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