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Magoosh
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This year, a woman has a lucrative one-year position. During this year, she will give a fraction f of her salary to her husband, a private investor, to invest and they will live this year on the remainder. Through investments, her husband can turn each dollar she gives him into 1 + r, which will be deposited in a bank account. Their goal is to save & invest enough money so they can live off this money for two years following the end of the wife's position. Toward this end, they want to choose f such that the amount in the account at the end of the year is twice what they lived off this year. In terms of r, what should f be?
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OG18 OG19 OG20 OG2022
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If x (2x + 1) = 0 and (x + $$\frac{1}{2}$$)(2x - 3) = 0, then x =
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190310
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e >d. Is ed < 0?
1:ed^2 >e^2d
2:e+d=1
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OG18 OG19 OG20 OG2022
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 Each of the 12 squares shown is labeled x, y, v, or w. What is the ratio of the number of these squares labeled x or y to the number of these squares labeled v or w?
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PREP07 Test 2
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There are 15 slate rocks, 20 pumice rocks, and 10 granite rocks randomly distributed in a certain field. If 2 rocks are to be chosen at random and without replacement, what is the probability that both rocks will be slate rocks?
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PREP07 Test 1
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A small water pump would take 2 hours to fill an empty tank. A larger pump would take 1/2 hour to fill the same tank. How many hours would it take both pumps, working at their respective constant rates, to fill the empty tank if they began pumping at the same time?
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190321 还原机经选题: 文字题&几何
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The probability of selecting each path is 1/2. What's the probability of getting to L from A?
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190310
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A, B is independent events. The probability of occurrence of event a is 1/3, and that of event B is 1/2. What is the probability of at least one occurrence in A and B?
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190310
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A belt connects the two rotating rollers. The length of the belt is 2m. The diameter of the rollers is 0.2m. What is the distance between the center of the two rollers?
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190321
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$$\frac{5!+6!+7!}{6!+7!+8!}$$ = ?
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190321
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There are 12 candies with four colors in an opaque bag. The proportion of red candy, yellow candy, white candy and green candy is 1/3,1/2,1/12,1/12, respectively. If two candies are taken out, what's the probability of picking at least one white candy out of this bag?
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which of the following CANNOT be a value of $$\frac{1}{x-1}$$
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OG12 OG15 OG16
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How many integers are there between, but not including, integers r and s ?(1)s-r= 10(2)There are 9 integers between, but not including, r + 1 and s + 1.
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OG12 OG15
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As x increases from 165 to 166, which of the following must increase?I 2x-5II $$1-\frac{1}{x}$$III $$\frac{1}{x^2-x}$$
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OG19-数学分册
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The sequence $$s_1$$, $$s_2$$, $$s_3$$, ... , $$s_n$$, ... is such that $$s_n= \frac{1}{n} -\frac{1}{n+1}$$ for all integers $$n\geq 1$$. If k is a positive integer, is the sum of the first k terms of the sequence greater than $$\frac{9}{10}$$?
(1) $$k>10$$
(2) $$k < 19$$
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Is y – x positive?(1) y>0(2) x = 1 - y
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190207
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Is xy-z > x-yz？
1：y > 1
2：x > 0
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OG18-数学分册
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If x + y = 2 and $$x^{2} + y^{2} = 2$$, what is the value of xy ?
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OG12 OG15 OG16
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if $$\frac{(4-x)}{(2+x)}= x$$, what is the value of $${x}^{2} + 3x - 4$$?
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PREP07 Test 2
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If a = 1 and$$\frac{(a-b)}{c}=1$$, which of the following is NOT a possible value of b ?
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