2012年12月22日SAT数学每日一题

2022-05-31 17:17:20

  下面是一道

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

  In the figure, the slope of the line through points P and Q is . What is the value of k?

  A.4

  B.5

  C.6

  D.7

  E.8

  答案及解析

  Correct Answer: B

  Here's Why:

  The slope of a line in a coordinate plane is given by the fraction whose numerator is the change in y between any two points on the line and whose denominator is the change in x between the same points on the line.

  The question asks for the value of k, which is the x-coordinate of point Q.

  The change in y between points P and Q is 7 – 1 = 6. The change in x between these points is k – 1. Since the slope is , it follows that = . Solving this equation gives 3k – 3 = 12. Therefore, 3k = 15, and k = 5.

  Difficulty: Medium

  Question Type: Standard Multiple Choice

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