题目问的不是1—p(A+B)吗

问题如下：

A risk analyst at an investment management firm interested in blockchain technology is monitoring the performance of a stablecoin project in an Asian country. The analyst finds that the project is regulated by a central monetary authority that will soon decide whether to distribute the stablecoins for public use, and notes that the following events could occur:

• Event A: The monetary authority distributes the stablecoins

• Event B: Businesses in the country accept the stablecoins as payment

The analyst also estimates the following probabilities: P(A): 70% , P(B): 40% ,P(B|A): 20%

What is the probability of either event A or event B occurring?

选项：

A.

0.29

B.

0.60

C.

0.84

D.

0.96

解释：

D is correct. Our goal is to find P(B U A), which is given by P(B U A) = P(A)+P(B)-P(BՈA). To calculate this, we first denote the following events:

Let P(A) = probability that the central monetary authority distributes the stablecoins to the public for use = 70%

P(B) = probability of businesses accepting stablecoins as payment = 40%

P(B|A) = probability of businesses accepting stablecoins as payment given that the central monetary authority distributes the stablecoins to the public for use = 20%.

From the following, we can obtain P(BՈA) = P(B|A)*P(A) = 0.20*0.70=0.14.

We want to find P(A U B) or P(B U A).

P(B U A) = P(A)+P(B)-P(BՈA) = 0.40+0.70-0.14 = 0.96 or 96%.

A is incorrect. This is P(B|A)/P(A).

B is incorrect. This is P(B|A)+P(B).

C is incorrect. This is P(BՈA)+P(A).