请教gwd数学30套 18-Q30 Q32

willingyue

有几道GWD想请教一下：
Q30:
From May 1 to May 30 in the same year, the balance in a checking account increased.  What was the balance in the checking account on May 30 ?
(1)        If, during this period of time, the increase in the balance in the checking account had been 12 percent, then the balance in the account on May 30 would have been $504.
(2)        During this period of time, the increase in the balance in the checking account was 8 percent.
       
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.

Q32:
What is the probability that event E or event F or both will occur?
(1)          The probability that event E will occur is 0.6.
(2)          The probability that event F will occur is 0.4.
       
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.
这题答案是E 是不是因为题目没有说这两个时间是相互独立的？
QX:
If the probability is 0.54 that Stock A will increase in value during the next month and the probability is 0.68 that Stock B will increase in value during the next month, what is the greatest possible value for the probability that neither of these two events will occur?

A.        0.22
B.        0.32
C.        0.37
D.        0.46
E.        0.63
这道变体题 不太理解问法为何是求the greatest possible value for the probability 是不是也是因为没有说两个事件是相互独立的？求解法
谢谢！！！！

willingyue

默默自己顶。。。。