下面是是2011年12月6日的SAT官方每日一题的内容，是关于数学方面的，题型是选择。SAT官方每日一题是collegeboard每天都会发布的题目，关于SAT考试的三个部分的各个题型。下面我们就一起来看一下这个SAT官方每日一题吧。

　　SAT官方每日一题之数学---选择：

　　Mathematics > Standard Multiple Choice

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　　Read the following SAT test question and then click on a button to select your answer.

　　A jar contains only red marbles and green marbles. If a marble is selected at random from the jar, the probability that a red marble will be selected is . If there are 36 green marbles in the jar, how many red marbles are there in the jar?

　　Answer Choices

　　(A) 18

　　(B) 24

　　(C) 54

　　(D) 72

　　(E) 108

　　The correct answer is D

　　Explanation

　　Choice (D) is correct. Let r be the number of red marbles in the jar. The probability of selecting a red marble is equal to the number of red marbles divided by the total number of marbles. Since the probability of selecting a red marble is , it follows that . There are 36 green marbles and r red marbles, so the previous equation becomes . This simplifies to2(r + 36) = 3r, or 2r + 72 = 3r. Therore, the number of red marbles, r, is 72.

　　下面是一道和SAT官方每日一题相似的题目，供大家练习：

　　The table above shows the temperatures, in degrees Fahrenheit, in a city in Hawaii over a one-week period. If represents the median temperature, represents the temperature that occurs most often, and represents the average (arithmetic mean) of the seven temperatures, which of the following is the correct order of , , and ?

　　Answer Choices

　　(A)

　　(B)

　　(C)

　　(D)

　　(E)

　　The correct answer is A

　　Explanation

　　Difficulty: Medium

　　To determine the correct order of , , and , it is helpful to first place the seven temperatures in ascending order as shown below.

　　The median temperature is the middle temperature in the ordered list, which is , so . The temperature that occurs most often, or the mode, is , so . To determine the average, you can add the seven numbers together and divide by . However, you can determine the relationship between the average and the median by inspection. The three numbers greater than are closer to than are the three numbers smaller than . Therore, the average of the seven numbers will be less than . The correct order of , , and is .

　　以上就是关于2011年12月6日SAT官方每日一题中数学选择题的详细内容，包括了题目和选项以及答案，后面附有一道相关的练习题。大家可以在备考SAT的过程中关注SAT每日一题的内容，这样就可以更好有不间断的练习，也就能在日积月累的过程中得到提高。

更多SAT官方每日一题：

2011年12月4日SAT官方每日一题---完成句子

2011年12月5日SAT官方每日一题---改进句子

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