GWD 数学题一道

scorpio2rd

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, 但是不知道为什么B 单独成立......

求指导......谢谢...

jesuischong

厄，我默认你要问的是A为什么成立

因为0.15X+0.29Y=4.40，x,y都必须是integer，所以只有当X=10，Y=10是才成立

B么……（0.15+0。29）*x=4.4

scorpio2rd

我其实是问的B, A 我明白,但是B里面, 你不知道4.4这个信息呀...

求解释.

多谢