Q26:
In the decimal representation of x, where 0 < x < 1, is the tenths digit if x nonzero?
(1) 16x is an integer.
(2) 8x is an 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.\
答案是B
请教大侠该如何解?
(注,只在x大于0,小于1的范围内成立)
B
条件二得出x是0.25(1/4)的倍数,如果0.25再乘以其他数十分位永远不可能是0
(注,只在x大于0,小于1的范围内成立)
B
cannot understand
why x is the multiple of 1/4 rather than 1/8??
how to understand the colored sentense??
thanks
不用再乘了
条件一得出X最小是1/16,X的十分位不定
条件二得出X最小是1/8,X的十分位不可能为0
我最简单的办法就是用数字试,
(1)假设16x=1, then x=0.0625, 16x=2, x=0.125, 所以不确定十分位是否是0;
(2)同理,8x=1, then x=0.125, 8x=2, x=0.25,十分位没有0的时候,如果不放心,在试8x=3,then x=0.375, 这是应试的方法。
所以选B, 不知道这样解释,是不是更好理解。
我觉得这个题目选的是E,
如果x=0.25,16x和8x是整数
如果X=0.5,16x和8x都是整数
因此是不确定的。
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