OG12两道Data Sufficiency题目的疑问

yangli317

1. Does the integer k have at least three different positive prime factors?

    

(1) k/15 is an integer

(2) k/10 is an integer

    

答案是C。 但我选的E。

我在想，假如k本身就是个负的integer，那答案就应该是E了啊。但是官方答案里没有考虑k是负整数的情况。请高人指点一下。

    

    

2. Of the 66 people in a certain auditorium, at most 6 people have
their birhtdays in any one given month. Does at least one person in the
auditorium have a birthday in January?

    

(1) More of the people in the auditorium have their birthday in February than in March.

(2) Five of the people in the auditorium have their birthday in March.

    

答案是D。但我选的B。

对于statement 
(2)，我没有异议，是sufficient。但是对于(1)，如果6个人生日在二月而0个人生日在三月，也符合statement
(1)的说法More of the people in the auditorium have their birthday in
February than in March，但是这样一来，就没有人生日在一月。所以我觉得statement (1)不是sufficient。


    

请高人指导下这两题。

polucn

极端假设，所有有人过生日的月份，都有6个人，那么只需要11个月，要使1月有人过生日，只要任意其他月满足<6就可以，所以1、2都成立

polucn

关于第一题，如果是个负整数，那么他是否也满足k至少等于=（—1）×2×3×5呢？

-1总不是质数吧