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SAT官方每日一题附答案和解析[数学](2015年6月24日)
日期:2015-06-24 12:34

(单词翻译:单击)

每日一题

Mathematics>Standard Multiple Choice


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

It costs d dollars to ship a package that weighs p pounds if and only if 6 is less than or equal to p is less than or equal to 10. If Alan's package weighs p pounds and costs d dollars to ship, which of the following must be true?

(A) |p-6| is less than or equal to 2
(B) |p-10| is less than or equal to 2
(C) |p-8| is less than or equal to 2
(D) |p+6| is less than or equal to 10
(E) |p+10| is less than or equal to 6

答案和解析

答案:C

解析:

If Alan's package weighs p pounds and costs d dollars to ship, then 6 is less than or equal to p is less than or equal to 10. Subtracting 8 across these inequalities gives the equivalent (6-8) is less than or equal to (p-8) is less than or equal to (10-8), and so (-2) is less than or equal to (p-8) is less than or equal to 2. By the definition of absolute value, it follows that (absolute value of p-8) is less than or equal to 2 must be true.

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重点单词
  • definitionn. 定义,阐释,清晰度
  • multipleadj. 许多,多种多样的 n. 倍数,并联
  • equivalentadj. 等价的,相等的 n. 相等物