求助 Math1 Q30 谢了先

cedric0312

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
我选答案A 但是看到正确答案为D
是我有什么猫腻没看出来还是答案错了

cenya

没有理由是D啊，就一个条件X=Y，怎么能解出X=？

bennywang2usa

A咋单独求出来的？一个一个试？

反正C是一定能求出来滴~

cedric0312

由A得出的一个二元一次方程，可以直接求解

ardor

D肯定不对