Given: P(A) = 0.2, P(B) = 0.55, and P(A ∩ B) = 0.1. We are asked to find P(B ∩ Ac), which is the probability of event B occurring and event A not occurring.
Step 1: Use the formula for P(B):
\[ P(B) = P(B \cap A) + P(B \cap A^c) \]
Step 2: Substitute the given values into the formula:
\[ 0.55 = 0.1 + P(B \cap A^c) \]
Step 3: Solve for P(B ∩ Ac):
\[ P(B \cap A^c) = 0.55 - 0.1 = 0.45 \]
Final Answer:
\[ 0.45 \]