Here is another question I find difficult to comprehend for me...

If Pr(A)=0.7, Pr (A Intersection B)=0.32 and the Pr(A` Intersection B`)=0.10, then the Pr (B)=

I know the formula Pr(A Union B)=Pr(A)+Pr(B)-Pr(A Intersection B) but don't know what the dashes mean and how to work out Pr(B)

In Set theory:

Complement of Union = Intersection of complements (Demorgan's Laws)

(A U B)` = (A` intersection B`)

Hence Pr (A U B)` = .10

Hence Pr (A U B) = 1 - .10 = .9
Hence

Pr (A) + Pr (B) - Pr (A intersection B) = .9

Hence

.7 + Pr (B) - .32 = .9

Pr (B) = .9 - .7 + .32 = .52