有些GWD的不会..希望大家帮忙看看..菜鸟一头...
If a committee of 3 people is to be selected from among 5 married couples so that the committee does not include two people who are married to each other, how many such committees are possible?
A. 20
B. 40
C. 50
D. 80
E 120
Of the families in City X in 1994, 40 percent owned a personal computer. The number of families in City X owning a computer in 1998 was 30 percent greater than it was in 1994, and the total number of families in City X was 4 percent greater in 1998 than it was in 1994. What percent of the families in City X owned a personal computer in 1998?
A. 50%
B. 52%
C. 56%
D. 70%
E. 74%
第一题C(3,10)-C(1,5)C(1,8) 从所有可能里把抽到一对夫妻的可能减去
第二题 就是设94年有X家庭，代进去算呀。the total number of families in City X was 4 percent greater in 1998 than it was in 1994 这是指98年比94年家庭数多4%，不是PC数哦。
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