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标题: SAT Question of Today
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发表于 2002-10-4 22:06  资料 主页 短消息  QQ
SAT Question of Today

This type of question consists of two quantities, one in Column A and one in Column B.
You are to compare the two quantities and click on the choice that best describes how the two quantities compare.

Note: In some questions, information is given about one or both of the quantities to be compared. In such cases the given information is centered above the two columns.

A symbol that appears in both columns represents the same thing.

Letters such as x, n, and k stand for real numbers.
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发表于 2002-10-4 22:06  资料 主页 短消息  QQ
5 < xy < 20 and x and y are integers.
Column A Column B
xy  x + y  


1 the quantity in Column A is greater
2the quantity in Column B is greater
3the two quantities are equal
4the relationship cannot be determined
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发表于 2002-10-4 22:09  资料 主页 短消息  QQ
hint

You know that xy has to be one of the integers between 5 and 20. You could start by considering the possible values of x and y for xy = 6 and what x + y would be for each pair.
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发表于 2002-10-4 22:10  资料 主页 短消息  QQ
Here's why:


Since x and y are integers, xy must be an integer, and the problem states that xy is between 5 and 20. If for example, xy = 6, then the values of x and y could be 6 and 1, 2 and 3, -6 and -1, or -2 and -3. For these values, x + y is 7, 5, -7, or -5, respectively, and in every case xy is 6. In some cases x + y is greater than 6 and in some cases x + y is less than 6. Since the relationship between xy and x + y varies, depending on which values of x and y are taken, the relationship between the quantity in Column A and the quantity in Column B cannot be determined.
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发表于 2002-10-4 22:11  资料 主页 短消息  QQ
Difficulty:

Hard

do u get it?
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