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标题: 跪求数学大神帮忙解一下题！万分感谢 [打印本页]

作者: flpalmbeach 时间: 2017-10-21 21:27
标题: 跪求数学大神帮忙解一下题！万分感谢

At least 100 students at a certain high school study Japanese. If 4 percent of the students at the school who study French also study Japanese, do more students at the school study French than Japanese?

(1) 16 students at the school study both French and Japanese.

(2) 10 percent of the students at the school who study Japanese also study French.

选B

A construction company was paid a total of $500,000 for a construction project. The company's only costs for the project were for labor and materials. Was the company's profit for the project greater than $150,000?

(1) The company's total cost was three times its cost for materials.

(2) The company's profit was greater thanits cost for labor.

选C

If each term in the sum a1 + a2 + . . . + an is either 7 or 77 and the sum equals 350, which of thfollowing could be equal to n?

(A) 38

(B) 39

(D) 41

(E) 42

选C

作者: Annie_wei 时间: 2017-10-21 23:30
第二题
P=profit
C= total cost
M=material cost
L=labor cost
(1) C=3M
(2) P>L
P=500,000-C
C=M+L
从（1）中得出 3M=M+L --->M=1/2L 则 C=3/2L
(2)中可以知道P>L 也就是500,000-3/2L>L ---->L<200,000 ---->P>200,000

第三题
77是7的十一倍 350/7=50 也就是说如果全是7的话有50items 有一个77就可以抵消11项
（1）一个77+39个7=40
（2）2个77+28个7=30 以此类推

作者: flpalmbeach 时间: 2017-10-22 00:30

Annie_wei 发表于 2017-10-21 23:30
第二题
P=profit
C= total cost

谢谢你哦祝你好运连连

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