# Math Help - random prob

1. ## random prob

Consider two people being randomly selected. What is the probability that two people were born on Friday?how can i solve this?

2. The probability that person 1 is born on a Friday is:

$P(X_1=F) = \frac{1}{7}$

and the probability that person 2 is born on a Friday is:

$P(X_2=F) = \frac{1}{7}$

so both would be $P(X_2=F) \times P(X_1=F) = \frac{1}{7} \times \frac{1}{7} = \frac{1}{49}$

3. What is the probability that two people have a birthday in August?

4. $P(X_1= Aug) = \frac{1}{12}$

$P(X_2= Aug) = \frac{1}{12}$

same argument as before

$P(X_1= Aug) \times P(X_2= Aug) = \frac{1}{12} \times \frac{1}{12} = \frac{1}{144}$

5. Originally Posted by lllll
$P(X_1= Aug) = \frac{1}{12}$

$P(X_2= Aug) = \frac{1}{12}$

same argument as before

$P(X_1= Aug) \times P(X_2= Aug) = \frac{1}{12} \times \frac{1}{12} = \frac{1}{144}$
Assuming the one is equally likely to be born on any day in the year the ptobability that one is born in August is 31/363.25

RonL