2.DS题,说农场里有animals 60头,其中2/3either猪or牛,问猪(或者牛)的数目是多少?
(1) the number of cow is more than twice as many as the number of pigs.
(2)pigs的数more than 12
[确认]C
我选E
3 .problem solving有一道新题看不太懂,我背了下来,请大家补充,谢谢!
the prosibility of A increased is 54%, the prosibility of b increased is 68%, what's the "greatest prosibility of neither of the 2 event occur"?
a) 22%, b) 32% , c) 37%, d)46%, e)??
[思路]这是求两个事件都不发生的概率吧。
我选32,完全重合,取最大的补集,
最小的话,应该是22,大家呢?
From 1): C : P can be 30 - 10; 29 - 11; 28 - 12........
2) alone is not sufficent.
combine: only one possibility: C : P = 27 : 13. for 26:14, 26 is less than 2 X 14.