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2012年11月14日SAT官方每日一题---数学选择

  下面是2012年11月14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 length of a rectangle is increased by20%, and the width of the rectangle is increased by30%. By what percentage will the area of the rectangle be increased?

  (A)25%

   (B)36%

   (C)50% 

  (D)56% 

  (E)60% 

  The correct answer is D

  Explanation

  Letlandwbe the original length and width of the rectangle, respectively. If we denote byLandWthe new length and width of the rectangle, respectively, then we have:L = l + ((20 over 100) times l) = 1.2 times landW = w + ((30 over 100) times w) = 1.3 times w

  So, the new area will be:A = L times W = (1.2 times l) times (1.3 times w) = 1.56 times (l times w) 

  1.56 times (l times w) = (l times w) + ((56 over 100) times (l times w))where (l times w) is the original area of the rectangle.

  So the area is increased by56%.

  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

  In an 8-gramsolution of water and alcohol, the ratio by mass of water to alcohol is 3to 1. If 12grams of a solution consisting of 2grams water for each gram of alcohol is added to the 8-gramsolution, what fraction by mass of the new solution is alcohol?

   Answer Choices

  (A) 1 over 6 

  (B) 3 over 10 

  (C) 5 over 12 

  (D) 7 over 12 

  (E) 5 over 24 

  The correct answer is B

  Explanation

  To find what fraction by mass of the new solution is alcohol, you can find how many grams of alcohol are in the final solution of 20grams. Since the 8-gramsolution is 1part alcohol to 3parts water, it is 1 over 4alcohol. So it contains 2grams of alcohol. Similarly, the 12-gramsolution is 1 over 3alcohol by mass, so it contains 4grams of alcohol. Thus, the final 20-gram solution contains 6grams of alcohol, so 6 over 20, or 3 over 10, of it is alcohol.

  以上就是关于2012年11月14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。