求救：涛涛30套Q18

chengzhiying

If k is a positive integer, is k the square of an integer?

(1)   k is divisible by 4.

(2) k is divisible by exactly 4 different prime numbers.                  

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE is sufficient.

E. Statements (1) and (2) TOGETHER are NOT sufficient.

答案是E，为什么不是B呢？exactly 4 different 难道不是只有4个质因数的意思吗，比如说2，3，5，7这四个数。可是是他们的平方吗？

谢谢~~~bow~~

suibian

B说是四个不同质数的倍数，但不一定只是四个质数的乘积 比如 2*3*5*7*2*3*5*7