Jon S. answered 04/28/22
Patient and Knowledgeable Math and English Tutor
Using probability rules:
GIven:
P(S) = 0.5
P(I) = 0.7
P(not (S or I)) = 0.2
Using complement rule:
P(S or I) = 1 - 0.2 = 0.8
Rule for computing either or both
P(S or I) = P(S) + P(I) - P(S and I)
substituting:
0.8 = 0.5 + 0.7 - P(S and I)
0.4 = P(S and I) ---- agreement on both sides