2007 AMC 8 第 21 题
先试着解答 2007 AMC 8 第 21 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 2007 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。
21.
从一副牌中发出两张牌。这副牌有四张红牌，分别标为 、、、，还有四张绿牌，也分别标为 、、、。一对获胜牌是两张同色牌或两张同字母牌。抽到一对获胜牌的概率是多少？
Two cards are dealt from a deck of four red cards labeled and four green cards labeled A winning pair is two of the same color or two of the same letter. What is the probability of drawing a winning pair?
小提示：
抽出第一张牌后，数有利的第二张牌
After the first card is drawn, count favorable second cards.
大提示：
第一张牌被移除后，同色牌和同字母牌不会重叠
The same-color cards and same-letter card do not overlap after the first card is removed.
解答：
抽出第一张牌后，还剩 张。其中 张同色， 张同字母。因此会与第一张牌形成获胜牌对的有 张，它们都在剩余的 张牌中。
概率为 。
所以正确答案是 D。
After drawing the first card, there are left. of them have the same color, and of them has the same letter. Therefore, there are out of possibilities that result in a winning pair.
The probability of drawing a pair is then
Thus, D is the correct answer.
其他年份的第 21 题
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- 1986 AMC 8
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- 1989 AMC 8
- 1990 AMC 8
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