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In a corporation, 50 percent of the male employees and 40percent of the female employees are at least 35 years old. If 42 percent of all the employees are atleast 35 years old, what fraction of the employees in the corporation arefemales?

A. 3/5

B. 2/3

C. 3/4

D. 4/5

E. 5/6

参考答案：D

题目翻译：50%男和40%女35岁及以上，共42%35岁及以上，女的占公司多少。

题目全解：

男a女b, 0.5a+0.4b=0.42(a+b);得b=4a，b/(a+b)=4/5.

There are 11 women and 9 men ina certain club. If the club is to selecta committee of 2 women and 2 men, how many different such committees arepossible?

A. 120

B. 720

C. 1,060

D. 1,520

E. 1,980

参考答案：E

题目翻译：11女9男，选2男2女，几种选法?

题目全解：C(2,11)*C(2,9)=(11*10*9*8)/4=1980

Is the sum of the integers x and y a prime number?

(1) x is an even prime number.

(2) y is a prime number between10 and 20.

A. Statement (1) ALONE is sufficient, but statement(2) alone is not sufficient.

B. Statement (2) ALONE is sufficient, but statement(1) alone is not sufficient.

C. BOTH statements TOGETHER are sufficient,but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE is sufficient.

E. Statements (1) and (2) TOGETHER are NOTsufficient.

参考答案：E

题目翻译：x和y的和是不是质数?

题目全解：(1)2 is the only prime even number. We don't know what Y is. Insufficient;

(2)Y can be 11,13,... We don't know what X is. Insufficient;

Together,2+11 = 13 Prime; 2+13 = 15 not Prime. Insufficient.

Hence E.