作者currycurry (古锥仔)
看板GMAT
标题[问题] OG-11th-Diagnostic Test-DS #25
时间Mon May 5 00:04:08 2008
If the units digit of integer n is greater than 2, what is the units digit
of n?
(1) The units digit of n is the same as the units digit of n^2.
(2) The units digit of n is the same as the units digit of n^3.
答案是 (E) both statements together are still not sufficient.
想问的是：
OG解释中的(2)：
Once again, 5 and 6 are the only numbers which, when cubed, will both have
a 5 or 6 respectively in their units digit.
个人认为，应该还有 4 及 9，也符合三次方之後，个位数仍相同的条件
是否有人有相同看法？
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※ 编辑: currycurry 来自: 140.116.138.235 (05/05 00:06)
1F：推 Engedi:OG的意思是说 将(1)(2)条件都考虑 也只能得出5 or 6的答案 05/05 00:11
2F：→ Engedi:未知数算出来不是唯一解就视为条件不足 你想的4or9 也同理 05/05 00:12
3F：→ currycurry:感谢,答案是了解，但单独对(2)的说明，认为应包含4,9 05/05 12:43