请问这两道gwd数学答案错了吗？

hebeqiao

Q26:只有0.5满足条件1和2，所以应该选d ,答案错了吗？

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.

Q34:n只能为3，应该选d, 怎么答案是b 呢？

What is the value of the integer n?

(1)
      n(n + 2) = 15

(2)
      (n + 2)ⁿ = 125

              

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.

[此贴子已经被作者于2008-1-8 8:16:36编辑过]

cloudymind

Q26, 16x is integer, x can be 0.125,or 0.0675 or ... 8x is integer, x has to be larger than 0.1

Q34, 15 = 3*5 = (-5)*(-3)

hebeqiao

多谢多谢！但是在Q26中，你怎么想到的0.125,or 0.0675 乘16为整数呢？

cloudymind

没那么想，就是想8*要是整数，8*要大于1，那么原来的肯定要大于0.1，而16*就要求不高，原来的大于小于0.1都可以

hebeqiao

你真聪明，谢谢啦