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题目： If r > 0, is rs < 0 ?(1) s < 0(2) s < r

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题目： When the positive integer n is divided by 13, the remainder is 4. What is the remainder when 2n – 3 is divided by 13 ?

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题目： The average (arithmetic mean) cost per book for the 12 books on a certain table is k dollars. If a book that costs 18 dollars is removed from the table and replaced by a book that costs 42 dollars, then in terms of k, what will be the average cost per book, in dollars, for the books on the table?

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题目： The sequence $${a}_{1}$$, $${a}_{2}$$, ..., $${a}_{n}$$, ... is such that $${a}_{n}=4a_{n-1}-{3}$$ for all integers $$n > 1$$. If $${a}_{3}={x}$$, then $${a}_{1}$$ =

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题目： The figure shows two squares, and the points W, X, Y, and Z lie on a line. If the distance between W and X is equal to the distance between X and Y and to the distance between Y and Z, then the area of the smaller square is what fraction of the area of the larger square?

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题目： If X, Y, and Z are positive integers, is Y >X?(1) $${Y}^{2}={X}{Z}$$(2) Z-X >0

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题目： The tens digit of positive integer X is 3. Is the units digit of X greater than 4?(1) The units digit of 2X is less than the units digit of X.(2) The tens digit of 2X is 7.

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题目： If $$x\neq y$$, is x+y=xy?(1) (1-x)(1-y)=1(2) $${x}^{2}-{y}^{2}={x}^{2}{y}-{x}{y}^{2}$$

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题目： A shipment of 8 television sets contains 2 black-and-white sets and 6color sets. If 2 television sets are to be chosen at random from this shipment, what is the probability that at least 1 of the 2 sets chosen will be a black-and-white set?

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题目： Of the three-digit positive integers that have no digits equal to zero, how many have two digits that are equal to each other and the remaining digit different from the other two?

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题目： If $${X}^{2}+{Y}^{2}={1}$$, is X+Y=1?(1) XY=0(2) Y=0

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题目： Of the 32 students in a certain class, 15 are in a music club and 20 are in a dance club. If 10 of the students are not in either club, how many of the students are in only one of the two clubs?

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题目： $${10},{000}^{100}$$ is equivalent to which of the following?I. $$({100}^{2})({100}^{100})$$II. $${100}^{200}$$III. $${10}^{400}$$

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题目： A certain carton holds fewer than 50 books. What is the number of books in the carton?(1) The books in the carton can be divided into 3 stacks of X books each, with 2 books left over.(2) The books in the carton can be divided into Y stacks of 7 books each, with 2 books left over.

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题目： In the xy-plane, the points (c, d), (c, -d), and (-c, -d) are three vertices of a certain square. If c < 0 and d > 0, which of the following points is in the same quadrant as the fourth vertex of the square?