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题目： If x percent of 40 is y, then 10x equals

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题目： If the number 52,1n9, where n represents the tens digit, is a multiple of 3, then the value of n could be which of the following?

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题目： The operation $$O$$ is defined by the equation $$x O y$$ = $$\frac{x-y} {x+y}$$, where $${y}!=-{x}$$. If $$3 O y = 5 O 4$$, then y =

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题目： If the average (arithmetic mean) of x, y, and 20 is 10 greater than the average of x, y, 20, and 30, what is the average of x and y?

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题目： Is |x|=|y|?(1)x - y = 6(2)x + y = 0

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题目： A certain company's profit in 1996 was 15 percent greater than its profit in 1995, and its profit in 1997 was 20 percent greater than its profit in 1996. The company's profit in 1997 was what percent greater than its profit in 1995?

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题目： In the xy-plane, is the slope of line k positive?(1)Line k passes through the points (-1, -7) and (2, 5).(2)Line k has equation y = 4x - 3.

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题目： The figure above represents a square garden that is divided into 9 rectangular regions with indicated dimensions in meters. The shaded regions are planted with peas, and the unshaded regions are planted with tomatoes. If the sum of the areas of the regions planted with peas is equal to the sum of the areas of the regions planted with tomatoes, what is the value of x?

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题目： In the xy-plane, the point (-2, -3) is the center of a circle. The point (-2, 1) lies inside the circle and the point (4, -3) lies outside the circle. If the radius r of the circle is an integer, then r =

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题目： In the xy-plane, line l and line k intersect at the point $$(\frac{16} 5,\frac{12} 5)$$. What is the slope of line l?(1)The product of the slopes of line l and line k is -1.(2)Line k passes through the origin.

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题目： Professor Vasquez gave a quiz to two classes. Was the range of scores for the first class equal to the range of scores for the second class?(1)In each class, the number of students taking the quiz was 26, and the lowest score in each class was 70.(2)In each class, the average (arithmetic mean) score on the quiz was 85.

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题目： If r, s, and t are positive integers, is r + s + t even?(1)r + s is even.(2)s + t is even.

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题目： A driver completed the first 20 miles of a 40-mile trip at an average speed of 50 miles per hour. At what average speed must the driver complete the remaining 20 miles to achieve an average speed of 60 miles per hour for the entire 40-mile trip? (Assume that the driver did not make any stops during the 40-mile trip.)

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题目： A wholesaler bought 1,200 radios for $18 each. The wholesaler sold 60 percent of the radios for $30 each and the rest for $15 each. What was the wholesaler's average (arithmetic mean) profit per radio?

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题目： If x and y are integers, is x + y greater than 0?(1)x is greater than 0.(2)y is less than 1.