Answer:
[tex]P(D|M) = \frac{5}{9}[/tex]
Step-by-step explanation:
Given
The sample space
Required
Probability that D is chosen at least twice provided that M is chosen first
First, list out all outcomes where M is selected first
[tex]M = \{MDA,,MAA,MAM,MAD,MMA,MMM,MDM,MDD,MMD\}[/tex]
[tex]n(M) = 9[/tex]
Next, list out all outcomes where D appears at least 1 when M is first
[tex]D\ n\ M= \{MDA,MAD,MDM,MDD,MMD\}[/tex]
[tex]n(D\ n\ M) = 5[/tex]
So, the required probability is:
[tex]P(D|M) = \frac{n(D\ n\ M)}{n(M)}[/tex]
[tex]P(D|M) = \frac{5}{9}[/tex]