Question

P(A)=25,P(B|A)=920,P(A∩B)=?

Answer 1

Hi! Let me help you!
This problem is a Venn Diagram question. It is much easier to answer this question with the visual it usually comes with. However, we can employ logic to give this one a smart and logical answer.

What we have so far:
P(A) =  25. This means that the shaded area of A is equal to 25.
P(B/A) = 920. This means that area A subtracted 25 to the value of area B which resulted to 920.
P(B) = 945. How did I arrive with 945? Simple, I just added 25 to 920. Go and be a smart lad and find why I did that.

Solution:
Solving P(A∩B) is quite challenging because like I said, a visual is needed for us to give it a pefect answer. Employing logic and using what we have so far:

If P(A∩B) means A and B intersection, we can assume that it is simply as A + B. 

If that is the case, then we can simply pull out our P(A) and P(B), 25 and 945 respectively and add them:

P(A) + P(B) = P(A∩B)
P(A∩B) =  25 + 945
P(A∩B) = 970 <----- What we are looking for

Therefore, P(A∩B) = 970!