两条GMAT数学题.第二题好像除了答案其他也有选项是不可能的,所以不知道为何选那个.1.samandjessicaareinvitedtoadance.ifthereare7menand7womenintotalatthedance,andonemanarechosentoleadthedance,wha

Question

两条GMAT数学题.第二题好像除了答案其他也有选项是不可能的,所以不知道为何选那个.
1.sam and jessica are invited to a dance.if there are 7 men and 7 women in total at the dance,and one man are chosen to lead the dance,what is the probability that sam and jessica will NOT be chosen to lead the dance.
2.(线段图简单,)
on the number line above,the segment from 0 to 1 has been divided into fifths,as indicated by the large tick marks,and also into sevenths,as indicated by the small tick marks.what is the least possible distance between any two of the tick marks?
A 1/70
B 1/35
C 2/35
D 1/12
E 1/7
第一题题目少打了两个词，应该是7男7女中选一男一女领舞，不是就选一个男的。
第二题我知道了。问题的意思我搞错了，理解为“最不可能的。”应该是最小可能的。

Answer 1

（1）7男7女14个人选一男一女领舞,每个人被选中概率为1/7,
sam(男)和Jessica(女)都不被选中的概率为：(1-1/7)×(1-1/7)=36/49
（2）选B.有两对点挨得最近,2/5处与3/7处 、4/7处与3/5处 都是相距1/35距离