A and B are independent events P(A)=.60 and P(B)=.40Find P(A intersection B) and P(A union B)

Question

This is confusing because where it says the P (B) is .60 the B has a line over it...I'm not clear what that means and I don't know how to put that into my calculator. The intersection is represented by upside down U and the union is represented by a regular U. When I put the P(.60 intersection .40) in the calculator, it gives me a question mark in front of the .40 which I'm thinking might have something to do with the fact that the B has that line above it....

Answer 1

B̄ probably means not-B, so P(B̄)=1-0.40=0.60, and P(A∩B̄) means probability of A and not-B=P(A)P(B̄)=0.60×0.60=0.36.

P(A∪B̄)=P(A)+P(B̄)-P(A)P(B̄)=1.20-0.36=0.84.