求教一道数学题 数据充分性

xiaotangyu

At Consolidated Foundries，for a resolution to become policy,a quorum of at least half the 20 directors must pass the resolution by at least a 2/3 majoriety.At a meeting of the  board of the directors,did resolution X pass or fail？
1.ten directors voted for the resolution
2.seven directors voted against the resolution

题目怎么理解呢 尤其是这句a quorum of at least half the 20 directors must pass the resolution by at least a 2/3 majoriety

xiaotangyu

答案是B

mandying

就是说，要使一个方案变成制度，20位directors里面至少要有一半就是10个人参与投票，而且还要2/3通过

1的话只能知道到达了法定人数，不知道有没有2/3
2的话可以推出就算剩下的13个人都投了赞同票，还是达不到2/3，肯定是没有通过   ( 7 > 1/3 )

所以B

xiaotangyu

vote for 不就是投票赞成吗 !

mandying

这样理解的话1也是不行的，因为你不知道多少directors投票了

可能11也可能20