求助 TT GWD31 18-32 和 其后的一道Qx

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.

答案是E, 怎么做的？

 由于题目没有讲E和F的合集就是全集，所以是错的，这种题目很阴险，注意。

要有做逻辑题目的那种不说的就当作不知道来做这种题目

 由于题目没有讲E和F的合集就是全集，所以是错的，这种题目很阴险，注意。

要有做逻辑题目的那种不说的就当作不知道来做这种题目

 由于题目没有讲E和F的合集就是全集，所以是错的，这种题目很阴险，注意。

要有做逻辑题目的那种不说的就当作不知道来做这种题目

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

答案是B, 怎么做的?

我一点idea都没有。请问这类题目应该怎么做？