a survey asked about the number of people who eat breakfast almost every day (b) and the number of people…

a survey asked about the number of people who eat breakfast almost every day (b) and the number of people who buy cereal at least once a month (c). the results of the survey are shown in the venn diagram. given that a randomly chosen person eats breakfast almost everyday, what is the probability that the person also buys cereal at least once a month? (\frac{11}{64}) (\frac{11}{53}) (\frac{53}{64}) (\frac{53}{57})
Answer
Explanation:
Step1: Recall conditional - probability formula
The formula for conditional probability is $P(C|B)=\frac{P(B\cap C)}{P(B)}$. In terms of the number of elements in the Venn - diagram, $P(C|B)=\frac{n(B\cap C)}{n(B)}$.
Step2: Identify $n(B\cap C)$ and $n(B)$ from the Venn - diagram
From the Venn - diagram, the number of elements in the intersection $B\cap C$ is $n(B\cap C) = 53$, and the number of elements in set $B$ is $n(B)=11 + 53=64$.
Step3: Calculate the conditional probability
$P(C|B)=\frac{n(B\cap C)}{n(B)}=\frac{53}{64}$.
Answer:
$\frac{53}{64}$