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标题: please help! GWD-1-26 M [打印本页]

作者: jasonhercules 时间: 2004-12-7 14:37
标题: please help! GWD-1-26 M

Q26:

If the units digit of the three-digit positive integer k is nonzero, what is the tens digit of k?

(1) The tens digit of k + 9 is 3.

(2) The tens digit of k + 4 is 2.

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.

the answer is A, but why? Please help me! thanks

作者: fansongzhi 时间: 2004-12-7 17:42

由1），推出k的十位数是2。因为k的个位数>=1，所以k+9的结果肯定要进十位一个1，而结果的十位是3，所以k的十位是2。

由2），k=118 或者k=122,都可以得出结果的十位是2，但不能确定k的十位是1 or 2.

作者: jasonhercules 时间: 2004-12-7 22:45
ThX a lot

作者: mingzhu_du 时间: 2004-12-29 02:53
如何理解The tens digit of k + 4？是不是可以理解K的10位数加4？而不是K+9以后的十位数？这种理解震得很麻烦，请大牛指点

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