What is the value of P(AUB) if P(A∩B)=.90, P(A)=.40, P(B)=.75?

Question

What is the value of P(AUB) if P(A∩B)=.90, P(A)=.40, P(B)=.75. The formula is P(AUB) = P(A) + P(B) - P(A∩B)

Answer 1

As you've stated, P(A∪B) = P(A) + P(B) - P(A∩B). By direct substitution, we have

P(A∪B) = P(A) + P(B) - P(A∩B)

P(A∪B) = 0.40 + 0.75 - 0.90

P(A∪B) = 0.25