I'm not sure if I'm doing this right.

Question

Determine whether events A and B are independent.
P(A) =.5, P(B)= .7, P(AUB)= .85

P(AUB) = P(A) + P(B) - P(A∩B)
.5 +.7 - P(A∩B)
1.2-0.18=1.02
*0.18 because I solved for P(A∩B) in the previous question.