为什么有些数学题明明问的是数值，给的选项却是

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.

例如GWD1-9，1-10等

For all integers n, the function f is defined by f (n) = aⁿ, where a is a constant. What is the value of f (1)?

(1) f (2) = 100

(2) f (3) = -1,000

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.

是不是我读题的理解有问题？请大侠们指点一下。

BTW：我没有上过XDF的GMAT班，现在也不在国内，周围的朋友都没有考过GMAT，这个问题困扰了我两天了。

我以前只考过GRE，从没见过这种形式的数学题。

这是传说中的data sufficiency题，问的不是

What is the value of (x - y)⁴?

而是用

(1) The product of x and y is 7.

(2) x and y are integers.

这两个条件能不能求出 the value of (x - y)⁴?

A 用A能求出B求不出

B 用B能求出A求不出

C 用A和B一起作为条件才能求出

D 用A能求出，用也能B求出

E 用AB都求不出