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. Q30：我选A，TOPWAY给的参考答案是D
设买了X 个0。15的，Y个0。29的（X，Y为POSITIVE INTERGER）
（1）得0。15X+0。29Y=4。40
只有X和Y都等于10的时候
才成立,其他时候X,Y都不能同时为正整数
（2）得X=Y
但不知道0。15X+0。29Y=?
所以只有A成立 | 
