no
If there are 300,000,000 people in the US, then on average you share your birthday with over 82,000 people. Of course, if your birthday is 2/29, you would share it with about 1/4th of that number.
estimating about 5000
On average, in the entire world about twenty eight thousand people will have the same birthday as one another. In a room full of people, there should be two people who have the same birthday.
On average every day there are 1.9 million people celebrating their birthday. That is the total global population (7 billion) divided by the number of days in a year (365).
Approxiamately six million people are born share a birthday so if you were born on that day you share your birthday with about six million people.
twins
Everyone shares their birthday with someone or another.
justin
If they are related then they are twins?
The answer, on average, is 0. Normal people do not share skin.
There cannot be a definite answer. There can only be a probabilistic answer of the number of people who might be expected to share a birthday. However, in order to do that it is necessary to know how many people there are in the school. And since you have not bothered to share that crucial bit of information, I cannot provide a more useful answer.