再求助一道Math题目

白菜白菜

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.


这题1可以通过分类讨论发现有且仅有x y=10时成立
2就不理解了。。为什么答案选D

huangwei123

根据我手上的OG 选A  100%

白菜白菜

真的吗=。=那我就懂了~