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_2018年雅思考试时间

2012年12月2日SAT官方每日一题---数学选择

  下面是2012年12月2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

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

  The stopping distance of a car is the number of feet that the car travels after the driver starts applying the brakes. The stopping distance of a certain car is directly proportional to the square of the speed of the car, in miles per hour, at the time the brakes are first applied. If the car’s stopping distance for an initial speed of20miles per hour is17feet, what is its stopping distance for an initial speed of40miles per hour?

  (A)34feet

  (B)51feet

  (C)60feet

  (D)68feet

  (E)85feet

  The correct answer is D

  Explanation

  The stopping distance is directly proportional to the square of the initial speed of the car. Ifsrepresents the initial speed of the car, in miles per hour, anddrepresents the stopping distance, you have that the stopping distance is a function ofsand thatfunction d of s = c times (s^2), wherecis a constant. Since the car’s stopping distance is17feet for an initial speed of20miles per hour, you know that17 = c times 20^2. Therefore,c = 17 over 20^2 = 0.0425, and the car's stopping distance for an initial speed of40miles per hour is0.0425 times 40^2 = 68feet.

  下面是一道和SAT官方每日一题相似的题目,供大家练习:

  A geologist has 10rocks of equal weight. If 6rocks and a 10-ounce weight balance on a scale with 4rocks and a 22-ounce weight, what is the weight, in ounces, of one of these rocks?

  Answer Choices

  (A)4

  (B) 5

  (C) 6

  (D) 7

  (E) 8

  The correct answer is C

  Explanation

  Let requal the weight of each rock, in ounces. The weight on one side of the scale is (6 times r) + 10ounces and the weight on the other side is (4 times r) plus 22ounces. Since the two weights balance, you can write the equation (6 times r) +10 = (4 times r) + 22. Solving this equation yields r equals 6.

  以上就是关于2012年12月2日SAT官方每日一题中数学部分的详细内容,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。