Answer:
[tex]P(Mary) = (1 - p) * r[/tex]
Step-by-step explanation:
Given
[tex]p \to[/tex] Peter hits
[tex]r \to[/tex] Mary hits
Required
The probability that Mary wins
From the question, we understand that Peter throws the first.
If Mary is to win, then Peter has to lose his throw
Using the complement rule, the probability that Peter misses is:
[tex]p' = 1 - p[/tex]
So, the probability that Mary wins is:
[tex]P(Mary) = p' * r[/tex]
This gives:
[tex]P(Mary) = (1 - p) * r[/tex]