Combinatorics: MasterChef
Six equally-talented chefs, labeled 1 to 6, are competing in a cooking contest. What is the probability that Chef 2 finishes in second place and Chef 5 ranks among the top three?
Answer
There are 6! ways to order them in total (total outcomes). Now, for the favorable outcomes:
\[
\text{Case 1: place 1 and 2 fixed... the rest can be ordered in }4!
\]
\[
\text{Case 2: place 2 and 3 fixed... the rest can be ordered in }4!
\]
Hence,
\[
\frac{2 \times 4!}{6!} = \frac{1}{15}.
\]