2. The events \(A\) and \(B\) are independent. Given that \(\mathrm { P } ( A ) = 0.4\) and \(\mathrm { P } ( A \cap B ) = 0.12\), find
- \(\mathrm { P } ( B )\),
- \(\mathrm { P } ( A \cup B )\),
- \(\mathrm { P } \left( A ^ { \prime } \cap B \right)\),
- \(\mathrm { P } \left( A \mid B ^ { \prime } \right)\).