请教各位GWD No1 中的1道数学题的求解

这个是GWD No1中的数学第30题

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.

Answer:

答案是D。可是我觉得应该是C。因为我感觉statement 2 alone根本推不出应该买多少$0.15stamps。

请教各位啦！谢谢～

a

同意楼上的

其实可以快速解条件（1）的，你看价格一个0.29，一个0.15

证明买0.29的数量肯定是5的倍数，要不怎么可能最后价格4.4，百分位是0呢。

所以买0.29的数量就是5，10，15之类的

带入后会发现只可能是10啦

这题一开始也错了，以后注意陷阱就行，对个别数字要敏感