SAT官方每日一题(数学) 2011年8月5日_无忧雅思网_雅思预测_雅思机经_雅思考试_雅思资料下载_雅思名师

　　下面是是关于数学方面的2011年8月5日的SAT官方每日一题的内容，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

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

　　If , the value of can be which of the following?

　. 　　. 　　.

　　Answer Choices

　　(A) only

　　(B) only

　　(D) and only

　　(E) , , and

　　The correct answer is D

　　Explanation

　　Roman Numeral Answer Format

　　Roman Numeral : Can the value of be ?

　　You could test this answer by substituting for in the equation and seeing whether the result is true. But you can also reason this question out without substituting numbers:

　　If , then (negative (1 over 3))^2 is a positive number, because any nonzero number squared is positive.

　　If , then is negative.

　　So is negative and is positive.

　　Therefore, cannot be .

　　Mark Roman numeral with an “F” for false.

　　Roman Numeral : Can the value of be ?

　　This is a very easy substitution to make:　　

　　Roman numeral is true, so mark it with a “T” for true.

　　Roman Numeral : Can the value of be ?

　　Substitute for :

　　If , then .Also, x^2 = (1 over 3)^2 = 1 over 9 .

　　Roman numeral is true, so mark it with a “T” for true.

　　Check the Answers:

　　You now know whether each of the Roman numeral statements is true or false:is false.is true.is true.

　　Find the choice that says only and are true

　　下面为大家提供一些和这些SAT官方每日一题相似的题目，供大家练习：

　　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)

　　The correct answer is D

　　Explanation

　　Difficulty: Hard

　　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 .