代数-OG22-PS：第41-50题 练习册详情

1

If the units digit of $$\frac{5610.37}{10^{k}}$$ is 6, what is the value of k?

• 3
• 2
• 1
• -1
• -2

0人做过此题 平均耗时为0 平均正确率为 0%

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2

Mark and Ann together were allocated n boxes of cookies to sell for a club project. Mark sold 10 boxes less than n and Ann sold 2 boxes less than n. If Mark and Ann have each sold at least one box of cookies, but together they have sold less than n boxes, what is the value of n?

• 11
• 12
• 13
• 14
• 15

899人做过此题 平均耗时为9min33s 平均正确率为 70%

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3

The product of two negative numbers is 160. If the lesser of the two numbers is 4 less than twice the greater, what is the greater number?

• -20
• -16
• -10
• -8
• -4

597人做过此题 平均耗时为8min16s 平均正确率为 67%

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4

According to a certain estimate, the depth N(t), in centimeters, of the water in a certain tank at t hours past 2:00 in the morning is given by $${N}({t})=-{20}({t}-{5})^{2}+{500}$$ for $$0 \leq t \leq 10$$. According to this estimate, at what time in the morning does the depth of the water in the tank reach its maximum?

• 5:30
• 7:00
• 7:30
• 8:00
• 9:00

6450人做过此题 平均耗时为18min2s 平均正确率为 65%

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5

Alex deposited x dollars into a new account that earned 8 percent annual interest, compounded annually. One year later Alex deposited an additional x dollars into the account. If there were no other transactions and if the account contained w dollars at the end of two years, which of the following expresses x in terms of w ?

• $$\frac{w}{1+1.08}$$
• $$\frac{w}{1.08+1.16}$$
• $$\frac{w}{1.16+1.24}$$
• $$\frac{w}{1.08+(1.08)^2}$$
• $$\frac{w}{({1.08})^2+({1.08})^3}$$

9976人做过此题 平均耗时为17min49s 平均正确率为 48%

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6

Working simultaneously at their respective constant rates, Machines A and B produce 800 nails in x hours. Working alone at its constant rate, Machine A produces 800 nails in y hours. In terms of x and y, how many hours does it take Machine B, working alone at its constant rate, to produce 800 nails?

• $$\frac{x}{x+y}$$
• $$\frac{y}{x+y}$$
• $$\frac{xy}{x+y}$$
• $$\frac{xy}{x-y}$$
• $$\frac{xy}{y-x}$$

9998人做过此题 平均耗时为16min19s 平均正确率为 69%

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7

If $$\frac1 3$$ of the total number of marbles in the three bags listed in the table above are blue, how many marbles are there in bag Q?

• 5
• 9
• 12
• 23
• 46

552人做过此题 平均耗时为7min53s 平均正确率为 44%

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8

If k and n are positive integers such that n > k, the n k! + （n - k） • （k - 1）! is equivale nt to which of the following?

• k-n!
• k!-n
• (n-k)!
• n•(k+1)!
• n•(k-1)!

0人做过此题 平均耗时为0 平均正确率为 0%

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9

If x and y are positive numbers such that x + y = 1, which of the following could be the value of 100x + 200y?

I. 80

II. 140

III. 199

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

1325人做过此题 平均耗时为9min31s 平均正确率为 55%

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10

Jackie has two solutions that are 2 percent sulfuric acid and 12 percent sulfuric acid by volume, respectively. If these solutions are mixed in appropriate quantities to produce 60 liters of a solution that is 5 percent sulfuric acid, approximately how many liters of the 2 percent solution will be required?

• 18
• 20
• 24
• 36
• 42

1335人做过此题 平均耗时为14min16s 平均正确率为 48%

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