[求助]GWD-13-23

whitecloud

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.

请给个解体思路，谢谢啊～

robert

答:B

16＝2的4次方 。所以只需要考虑x是5的多少次方就可以。x=0.625或0.0625都是整数，A不对

8＝2的3次方。x的十分位必然不能为0，否则不会是整数

whitecloud

谢谢，不过还是糊涂，能把题干解释一下吗？谢谢啦

sammen

一个十进制的数X，0&lt;X&lt;1,问十分位上的数是非0的吗？