Given:
Numbers from 1 - 40
Let's find the probability of:
Pleven | at least 12)
Where:
Even numbers = 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40 = 20 numbers
Even numbers that are at least 12 = 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40 = 15 numbers.
Numbers that are at least 12 = 29 numbers
Therefore, to find the probability, we have:
[tex]P(even|atleast12)=\frac{P(even\text{ and at least 12\rparen}}{P(at\text{ least 12\rparen}}[/tex]Where:
[tex]\begin{gathered} P(even\text{ and at least 12\rparen = }\frac{15}{40}=0.375 \\ \\ P(at\text{ least 12\rparen= }\frac{29}{40}=0.725 \end{gathered}[/tex]Therefore, we have:
[tex]\begin{gathered} P(even|atleast12)=\frac{0.375}{0.725} \\ \\ P(even|atleast12)=0.52 \end{gathered}[/tex]Therefore, the probability that a number chosen at random is even given that it is at least 12 is 0.52
ANSWER:
0.52