GWD31套版 1-30 答案是不是错了？？

verylotus

Q30:

Joanna bought only $0.15 stamps and $0.29 stamps.  How many $0.15 stamps did she buy?

(1)     She bought $4.40 worth of stamps.

(2)     She bought an equal number of $0.15 stamps and $0.29 stamps.

                 

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.

答案选的D，我觉得不可能啊

我开始选的C，觉得用两个等式可以算出分别的个数

可是后来觉得只有A也是可以得到的，因为邮票只能买整数，可以用这个条件限定出来，不知道想的对不对，大家帮帮忙，谢谢！！

妈妈宝宝

只有当 $0.29 stamps 是5的倍数时，$0.15 stamps and $0.29 stamps 的和才可能是$4.40 。只有1个可能，就是10张$0.29 stamps 。  因为5张和15张$0.29 stamps ， 都买不了整数张$0.15 stamps 。

verylotus

恩，我也是这么觉得的，C选项比较迷惑，不知道答案为什么竟然选了D，诡异