If p is a positive integer, what is the value of p ?
(1) p/4 is a prime number
(2) p is divisible by 3.
Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
EACH statement ALONE is sufficient.
Statements (1) and (2) TOGETHER are NOT sufficient.
(1)p/4是个质数,设质数为n,p=4n。(2)4n能被3整除,说明n是个能被3整除的质数。能被3整除的质数只能是3,3再往上翻倍就不是质数了。
4n能被3整除,说明n是个能被3整除的质数。能被3整除的质数只能是3,3再往上翻倍就不是质数了
prime number素数,除了1和自身外不再有其他素数(因数)
1) p/4 为质数,则p可以为很多数。2)同一;1+2 p可以被4整除,也可以被3整除,那么p可以被12整除,因此p可以是12的倍数(12,24,48,60...) 。但是需要满足p/4是一个质数,因此只有12满足条件。
12
12
看完1就心中把p是质数当做题目已知条件了。。。