SAT数学科目是我们中国学生的强项，大家一定要发挥出自己的优势，这样才能提高SAT总分成绩，提升自己的申请竞争力，下面澳际小编为大家搜集出了2015年3月SAT数学几道真题预测，希望同学们要提前做好准备。

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

　　1、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

　　2、In the , line is perpendicular to the graph of the function . Line could be the graph of which of the following functions?

　　Answer Choices

　　(A)

　　(B)

　　(C)

　　(D)

　　(E)

　　3、A special lottery is to be held to select the student who will live in the only deluxe room in a dormitory. There are seniors, juniors, and sophomores who applied. Each senior's name is placed in the lottery times; each junior's name, times; and each sophomore's name, time. What is the probability that a senior's name will be chosen?

　　Answer Choices

　　(A)

　　(B)

　　(C)

　　(D)

　　(E)

　　Explanation

　　1、The correct answer is D

　　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.

　　2、The correct answer is B

　　If two lines are perpendicular, the product of their slopes is equal to . The function is in slope-intercept form, so the slope of the graph of is equal to . Therore, the slope of line must be equal to . The only choice that corresponds to a slope of is .

　　3、The correct answer is D

　　To determine the probability that a senior's name will be chosen, you must determine the total number of seniors' names that are in the lottery and divide this number by the total number of names in the lottery. Since each senior's name is placed in the lottery times, there are seniors' names. Likewise, there are juniors' names and sophomores' names in the lottery. The probability that a senior's name will be chosen is .

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　　在几何及度量方面，加入了特殊三角形的特征分析、多种切线特征知识、简单的坐标几何学、图形与函数的相互转换与表达等等;难题方面增加了数据分析、简单的矩阵、统计及概率分析的试题。

　　以上内容就是澳际小编为大家道搜集出的2015年3月SAT数学几道真题预测，希望对大家有所参考，距离3月14日考试只有不到两天了，本次考试集中在北美考区，澳际小编还是祝愿在美国考SAT的同学们能取得满意的成绩。

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