It can be shown that for any three events \(A, B\), and \(C\), the probability that at least one of them will occur is given by
\[\begin{aligned}
P(A \cup B \cup C)= & P(A)+P(B)+P(C) \\
& -P(A \cap B)-P(A \cap C) \\
& -P(B \cap C)+P(A \cap B \cap C)
\end{aligned}\]
Verify that this formula holds for the probabilities of Figure 3.13.

A B 0.24 0.06 0.19 0.04 0.16 0.11 0.09 0.11 C S Figure 3.13 Diagram for Exercise 3.49