Four people around a room. What is the probability that two (or more) of them have the same birthday?
However, I am not sure if my working out assume finds out about the 2 or more part. I am using the pigeon hole method the most suitable approach for answering this question
Here is my working out
$P(A)$ = 2 or more people having the same birthday
This is difficult to find. However, I can use the Pigeon Hole theory.
$P(A')$ = 2 people having the same birthday
Thus $P(A) = 1 - P(A')$
To calculate P(A')
$P(A') = (1/365)^4 * (365*364*363*362) $
$P(A') = 0.9836440875$
$P(A) = 1 - P(A')$
$P(A) = 1 - 0.9836440875$
$P(A) = 0.0163559125$
Thus it approx 1.635% that 2 or more people will have the same birthdays.
EDIT: For spelling errors and changing the value of P(A)