Step 1: Write out the formula
[tex]P(M\text{ or G) = P(M) + P(G) - P(M}\cap G)[/tex][tex]\begin{gathered} \text{where } \\ M\text{ and G are events} \end{gathered}[/tex]Step 2: Write out the given values and substitute them into the formula
Let M be the event for Mustache competition
Let G be the event for Grey Beard
n(M) = 3 + 2 + 3 = 8
n(G) = 4 + 2 = 6
n(GnM) = 4
n(U) = 16
Therefore,
[tex]P(M)=\frac{8}{16},P(G)=\frac{6}{16},P(M\cap G)=\frac{4}{16}[/tex][tex]\begin{gathered} P(M\text{ or G) = }\frac{8}{16}+\frac{6}{16}-\frac{4}{16} \\ =\frac{8+6-4}{16}=\frac{10}{16}=\frac{5}{8} \end{gathered}[/tex]Therefore, the probability that a randomly selected contestant has a grey beard or is only in the beard competition is 5/8