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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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In a large investment firm, 25 percent of the male employees and 30 percent of the female employees are stockbrokers. If 60 percent of the firm's employees are males, what is the ratio of the number of male stockbrokers to the number of female stockbrokers?
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OG12
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In a certain population, there are 3 times as many people aged 21 or under as there are people over 21. The ratio of those 21 or under to the total population is
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In the figure above, two circles with radii equal to 10 units of length overlap such that their centres, $${O}_{1}$$ and $${O}_{2}$$, are 16 units apart. What is the distance between the line joining the centres of the circles and the line drawn through point P parallel to the line connecting the centres?
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OG16 OG17 OG18 OG19 OG20 OG2022
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 In the figure above, what is the ratio of the measure of angle B to the measure of angle A?
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Manhattan
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On a fishing excursion, Jeannie keeps$$\frac{ 1}{4}$$ of the fish she catches and releases the remainder of the fish back into the lake. If $$\frac{2}{3}$$ of the fish she keeps are trout, and 1/3 of the fish she releases are trout, what proportion of the total number of fish she catches are trout?
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190415
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S is the total volume of 16 balls whose diameters are 1. C is the volume of 16 cylinders with a diameter of 1 and a height of 1.$$\frac{s}{c}$$=?
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190302
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The length of the three sides of a triangle is 6, x, 2x. What is the range of x?
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Magoosh
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If x and y are both positive and $$\sqrt{x^{2}+y^{2}} = 3x - y, then \frac{x}{y} =$$
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Magoosh
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A: {71,73,79,83,87} B:{57,59,61,67}If one number is selected at random from set A, and one number is selected at random from set B, what is the probability that both numbers are prime?
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Working alone at their respective constant rates, machine A and machine B can fill a certain order in 3 hours and 6 hours, respectively. If the two machines work simultaneously at their respective constant rates, how many hours does it take the two machines to fill 1/2 of that order?
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第一期
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If$$x = \sqrt{3} +\sqrt{7}$$ , what is the value of $$x+\frac{1}{x}$$ ?
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OG12 OG15 OG16 OG17 OG18
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At a certain school, the ratio of the number of second graders to the number of fourth graders is 8 to 5, and the ratio of the number of first graders to the number of second graders is 3 to 4. If the ratio of the number of third graders to the number of fourth graders is 3 to 2, what is the ratio of the number of first graders to the number of third graders?
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OG12 OG15 OG16
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A positive number x is multiplied by 2, and this product is then divided by 3. If the positive square root of the result of these two operations equals x, what is the value of x ?
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OG12 OG15
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lf x+5>2 and x-3<7, the value of x must be between which of the following pairs of numbers?
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排列组合
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A coin that is tossed will land heads or tails, and each outcome has equal probability. What is the probability that the coin will land heads at least once on two tosses?
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If $${n}=\sqrt{\frac{16}{81}}$$ what is the value of $$\sqrt{n}$$?
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KMFPS
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A box contains 100 balls, numbered from 1 to 100. If three balls are selected at random and with replacement from the box, what is the probability that the sum of the three numbers on the balls selected from the box will be odd?
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PREP07 Test 1
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In a certain deck of cards, each card has a positive integer written on it. In a multiplication game, a child draws a card and multiplies the integer on the card by the next larger integer. If each possible product is between 15 and 200, then the least and greatest integers on the cards could be
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PREP07 Test 1
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All of the stocks on the over-the-counter market are designated by either a 4-letter or a 5-letter code that is created by using the 26 letters of the alphabet. Which of the following gives the maximum number of different stocks that can be designated with these codes?
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