1989 AMC 8 第 13 题
先试着解答 1989 AMC 8 第 13 题，然后核对你的答案与精心整理的解答，解答来自 LIVE by Po-Shen Loh。你也可以参加完整限时模拟考试、查看全部 1989 AMC 8 解答，或核对答案。
所有题目均经美国数学协会（MAA）官方合法授权使用。
13.
下列哪个式子等于
Which of the following is equal to
小提示：
如果把分子除以十，分母中的某一个因数也必须除以十，分数值才不变
Dividing the numerator and one factor of the denominator by the same number keeps the fraction unchanged
大提示：
要把 变成 ，需除以 ；为保持分数值不变，也把分母中的一个因数除以
To turn into divide by to keep the value equal, divide one factor of the denominator by as well
解答：
将分子 除以 ，得到 。为了保持分数值不变，分母整体也要除以 ，即把其中一个因数除以 。
把分母中的因数 除以 ，而另一个因数保持不变，便得到 。其他选项会使原式改变 倍或 倍。
所以正确答案是 A。
To rewrite the numerator as divide it by To keep the fraction equal, divide the denominator by too, which means dividing one of its factors by
Dividing the factor by gives which equals the original. Each other choice changes the value by a factor of or
Thus, the correct answer is A .
其他年份的第 13 题
- 1985 AMC 8
- 1986 AMC 8
- 1987 AMC 8
- 1988 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
- 2001 AMC 8
- 2002 AMC 8
- 2003 AMC 8
- 2004 AMC 8
- 2005 AMC 8
- 2006 AMC 8
- 2007 AMC 8
- 2008 AMC 8
- 2009 AMC 8
- 2010 AMC 8
- 2011 AMC 8
- 2012 AMC 8
- 2013 AMC 8
- 2014 AMC 8
- 2015 AMC 8
- 2016 AMC 8
- 2017 AMC 8
- 2018 AMC 8
- 2019 AMC 8
- 2020 AMC 8
- 2022 AMC 8
- 2023 AMC 8
- 2024 AMC 8
- 2025 AMC 8
- 2026 AMC 8