请教各位牛牛

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.

答案是D  ,但是我不清楚的是，为什么条件2也成立呢，

 2单独不成立的.1单独成立.

选A吧?

条件12合并才成立啊,单独条件12应该都不成立呀.题目的意思应该是JOANNA只买

了０．１５美圆一张和0.29美圆一张的邮票,那么她买了多少张0.15美圆一张的邮票

呢?设0.15X张,0.29Y张,

(1)0.15X+0.29Y=4.4

(2)X=Y

所以两个单独都不成立,合并才成立啊,答案是不是有啥问题