2020 AMC 8 Problem 10
Attempt Problem 10 of the 2020 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 2020 AMC 8 solutions, or check the answer key.
All problems are used with official legal permission of the Mathematical Association of America (MAA).
10.
Zara has a collection of marbles: an Aggie, a Bumblebee, a Steelie, and a Tiger. She wants to display them in a row on a shelf, but does not want to put the Steelie and the Tiger next to one another. In how many ways can she do this?
Answer: C
Small hint:
Count all arrangements first
Big hint:
Subtract arrangements where Steelie and Tiger are treated as one block
Video solution:
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Written solution:
There are total arrangements of the marbles.
If the Steelie and Tiger are adjacent, treat them as one block. Then there are ways to arrange the block with the other two marbles, and orders inside the block, for adjacent arrangements.
Therefore, arrangements keep the Steelie and Tiger separated.
Thus, the correct answer is C.
Problem 10 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
- 1996 AMC 8
- 1997 AMC 8
- 1998 AMC 8
- 1999 AMC 8
- 2000 AMC 8
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