4. k 是整数, 问k(k+1)(k-1)能否被6整除?
A k>0
B k是3的倍数
我选B
讨论:k(k+1)(k-1) 代表的就是6的倍数,是否答案为d
[ 20 ]
2.100个人对选举人mn的态度,
支持 不支持 不明朗
m 40 20 40
n 35 35 30 (n的1.3数字不准)
100个人被调查,态度如上,问既支持m又支持n的人数
a)100个人中,对两人既不支持也不明朗的是40
b)100个人中,同时不支持mn的为20人(不确定数字)
讨论:这题是不是可以转化为支持m: 40, 非支持m, 60; 支持n, 35, 非支持n, 65. 这样用a) we get the overlap between supporters of a and b is 15. for b) we can only know those who didn’t support m did not support n, but no more.
2.已知B总数是240,学science的总数是140,Math 170 求 learn math but not Science? C
A. there are 55 who learn science but not math
B. there are 30 students did not selcet any subject
讨论:这题我认为是d, if we know a)we can get the overlap part140-55=95; b) the part a plus b is known作者: tongxun 时间: 2002-7-21 23:29