2018 AMC 8 Problem 5
Attempt Problem 5 of the 2018 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 2018 AMC 8 solutions, or check the answer key.
All problems are used with official legal permission of the Mathematical Association of America (MAA).
5.
What is the value of
Answer: E
Small hint:
Pair each positive odd number after with the even number just before it.
Big hint:
Count how many ’s remain after pairing.
Video solution:
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Written solution:
Rearranging the terms, notice that the expression in the question is equal to: Each term is equal to and there are terms, so the total sum is
Thus, E is the correct answer.
Problem 5 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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- 1998 AMC 8
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