Thread: Is an answer possible with the given information?

P(A U B) = .7 P(A U compliment of B) = .9

Find P(A)


I've racked my brain and cannot come up with an answer.

This is all I've managed to calculate, perhaps I'm just missing a connection.

P(A U compliment of B) = P(compliment of B)
P(B) = 1 - P(compliment of B) = .1
P(compliment of A intersect compliment of B) = 1 - P(A U B) = .3
P(A intersect compliment of B) = P(A U B) - P(B) = .6
P(A|compliment of B) =
P(A intersect compliment of B) / P(compliment of B) = 2/3
"This last one establishes dependence."

That is all I could come up with.

Originally Posted by bartoncl

P(A U B) = .7 P(A U compliment of B) = .9

Find P(A)


I've racked my brain and cannot come up with an answer.

This is all I've managed to calculate, perhaps I'm just missing a connection.

P(A U compliment of B) = P(compliment of B)
P(B) = 1 - P(compliment of B) = .1
P(compliment of A intersect compliment of B) = 1 - P(A U B) = .3
P(A intersect compliment of B) = P(A U B) - P(B) = .6
P(A|compliment of B) =
P(A intersect compliment of B) / P(compliment of B) = 2/3
"This last one establishes dependence."

That is all I could come up with.

[Note on spelling. Compliment is when you say something flattering about someone. Complement is "that which completes or makes up the whole".]

I'll write for the complements of A and B.

(you already got that one). In the same way,
. Then . Finally, .

Hello, bartoncl!

Find

Draw a two-circle Venn diagram . . . it will help.


We are given: .

Its complement is: .







Therefore: .