gwd29-13

tangyu84

13。For any positive integer x, the 2-height of x is defined to be the greatest nonnegative integer n such that 2ⁿ is a factor of x. If k and m are positive integers, is the 2-height of k greater than the 2-height of m ?

(1) k > m

(2) k/m is an even integer.

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.

这道题的正确答案是b，我不知道此题解题思路是什么，求教！

founder

我觉得碰到这样的题就是分别把条件代入题干，看是否满足，当不确定是否满足（即不容易证明时），可看是否有反例。

13。For any positive integer x, the 2-height of x is defined to be the greatest nonnegative integer n such that 2^n is a factor of x. If k and m are positive integers, is the 2-height of k greater than the 2-height of m ?
(1) k > m
(2) k/m is an even integer.

(1)k>m，不一定the 2-height of k greater than the 2-height of m ，比如k=6时， 2-height of k 为2，m=2时， 2-height of m 为2

(2)设k/m=2t,那必然the 2-height of k 比the 2-height of m大1