P(a)= .5, p(b)= .4, and p(a and b)= .15. what is p(a OR b)

Step-by-step explanation:

Hello

p(A∪B) = p(A) + p(B) - p(A∩B) = 0.5 + 0.4 - 0.15 = 0.9 - 0.15 = 0.75

hope this helps