Step 1	\(P[A \cup B]’ = 1 – P[A \cup B]\) \(P[A’ \cap B’] = 1 – 0,7\) \(P[A’ \cap B’] = 0,3\)
Step 2	\(P[A \cup B’]’ = 1 – P[A \cup B’]\) \(P[A’ \cap B] = 1 – 0,9\) \(P[A’ \cap B] = 0,1\)
Maka	\(P[A] = 1 – P[A’]\) \(P[A] = 1 – \left( {P[A’ \cap B] + P[A’ \cap B’]} \right)\) \(P[A] = 1 – \left( {0,1 + 0,3} \right)\) \(P[A] = 0,6\)
Jawaban	d. 0,6