PS-OG16：第221-230题 练习册详情

1

$$(\frac{1}{2})^{-3}(\frac{1}{4})^{-2}(\frac{1}{16})^{-1}=$$

• $${(\frac{1}{2}})^{-48}$$
• $${(\frac{1}{2}})^{-11}$$
• $${(\frac{1}{2}})^{-6}$$
• $${(\frac{1}{8}})^{-11}$$
• $${(\frac{1}{8}})^{-6}$$

4167人做过此题 平均耗时为15min0s 平均正确率为 70%

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2

List T consists of 30 positive decimals, none of which is an integer, and the sum of the 30 decimals is S. The estimated sum of the 30 decimals, £, is defined as follows. Each decimal in T whose tenths digit is even is rounded up to the nearest integer, and each decimal in T whose tenths digit is odd is rounded down to the nearest integer; E is the sum of the resulting integers. If $$\frac{1}{3}$$ of the decimals in T have a tenths digit that is even, which of the following is a possible value of E - S ?

I.-16

II.6

III.10

• I only
• I and II only
• I and III only
• II and III only
• I,II, and III

9983人做过此题 平均耗时为20min48s 平均正确率为 55%

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3

In a certain game, a large container is filled with red, yellow, green, and blue beads worth, respectively, 7, 5, 3, and 2 points each. A number of beads are then removed from the container. If the product of the point values of the removed beads is 147,000, how many red beads were removed?

• 5
• 4
• 3
• 2
• 0

9980人做过此题 平均耗时为8min48s 平均正确率为 64%

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4

Of the 200 students at College T majoring in one or more of the sciences, 130 are majoring in chemistry and 150 are majoring in biology. If at least 30 of the students are not majoring in either chemistry or biology, then the number of students majoring in both chemistry and biology could be any number from

• 20to50
• 40to70
• 50to130
• 110to130
• 110to150

2203人做过此题 平均耗时为2min56s 平均正确率为 66%

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5

If $$5-\frac{6}{x}=x$$ then x has how many possible values?

• None
• One
• Two
• A finite number greater than two
• An infinite number

7437人做过此题 平均耗时为17min0s 平均正确率为 65%

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6

Seed mixture X is 40 percent ryegrass and 60 percent bluegrass by weight; seed mixture Y is 25 percent ryegrass and 75 percent fescue. If a mixture of X and Y contains 30 percent ryegrass, what percent of the weight of the mixture is X ?

• 10%
• $${33}\frac{1}{3}\%$$
• 40%
• 50%
• $${66}\frac{2}{3}\%$$

7134人做过此题 平均耗时为36min34s 平均正确率为 56%

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7

A straight pipe 1 yard in length was marked off in fourths and also in thirds. If the pipe was then cut into separate pieces at each of these markings, which of the following gives all the different lengths of the pieces, in fractions of a yard?

• $$\frac{1}{6}$$ and $$\frac{1}{4}$$ only
• $$\frac{1}{4}$$ and $$\frac{1}{3}$$ only
• $$\frac{1}{6}$$, $$\frac{1}{4}$$, and $$\frac{1}{3}$$
• $$\frac{1}{12}$$, $$\frac{1}{6}$$, and $$\frac{1}{4}$$
• $$\frac{1}{12}$$, $$\frac{1}{6}$$, and $$\frac{1}{3}$$

8747人做过此题 平均耗时为40min49s 平均正确率为 61%

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8

Right triangle PQR is to be constructed in the xy-plane so that the right angle is at P and $$\overline{PR}$$ is parallel to the x-axis. The x- and y-coordinates of P, Q, and R are to be integers that satisfy the inequalities $$-4 \le x \le 5$$ and $$6 \le y \le 16$$. How many different triangles with these properties could be constructed?

• 110
• 1,100
• 9,900
• 10,000
• 12,100

7053人做过此题 平均耗时为34min7s 平均正确率为 42%

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9

How many of the integers that satisfy the inequality $${\frac{(x+2)(x+3)}{x-2}}\ge{0}$$ are less than 5 ?

• 1
• 2
• 3
• 4
• 5

7384人做过此题 平均耗时为33min26s 平均正确率为 41%

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10

The value of $$\frac{({2}^{-14}+{2}^{-15}+{2}^{-16}+{2}^{-17})}{5}$$ is how many times the value of$${2}^{-17}$$?

• $$\frac{3}{2}$$
• $$\frac{5}{2}$$
• 3
• 4
• 5

4035人做过此题 平均耗时为19min31s 平均正确率为 70%

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