\[\boxed{\mathbf{87.}}\]
\[P(A) = P(B) = 0,3;\]
\[P(A \cap B) = 0,12;\]
\[\textbf{а)}\ P(A \cup B) =\]
\[= P(A) + P(B) - P(A \cap B) =\]
\[= 0,3 + 0,3 - 0,12 = 0,48.\]
\[\textbf{б)}\ P(A \cup B) - P(A \cap B) =\]
\[= 0,48 - 0,12 = 0,36.\]