If m is a positive integer, then~$ m^3$~ has how many digits?

(1) m has 3 digits.

(2)~$ m^2$~ has 5 digits.


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.

考题讲解

题目分析:

(1)    m有三位数,例如m=100,~$m^3$~=1000000有7位数。又如m=300,则~$m^3$~有8位数,所以给定条件1不能确定~$m^3$~的位数。

(2)  例如m=100,~$m^2$~=10000,有5位数,满足条件2,但~$m^3$~有7位数。又如m=300,~$m^2$~=9000,有5位数,满足条件2,但~$m^3$~有8位数。所以给定条件2不能确定~$m^3$~的位数。

因此,本题答案为(E),两个条件结合起来也不能解题,必须提供新数据。

 

 

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