How many people must be there in a room to make the probability 100\% that at least two people in the room have same birthday?

How many people must be there in a room to make the probability 100\% that at-least two people in the room have same birthday? Answer: 367 (since there are 366 possible birthdays, including February 29).

What is the probability that at least two students share a birthday?

In a room of just 23 people there’s a 50-50 chance of at least two people having the same birthday. In a room of 75 there’s a 99.9\% chance of at least two people matching.

What is the probability of having the same birthday as someone else?

One person has a 1/365 chance of meeting someone with the same birthday. Two people have a 1/183 chance of meeting someone with the same birthday. Those two people might also have the same birthday, right, so you have to add odds of 1/365 for that. The odds become 1/365 + 1/182.5 = 0.008, or .

How many people need to be in a class before there is a greater than 50 chance that every day of the year someone has a birthday?

For a greater than 50\% chance that one person in a roomful of n people has the same birthday as you, n would need to be at least 253.

What is birthday paradox cryptography?

A birthday attack is a type of cryptographic attack, which exploits the mathematics behind the birthday problem in probability theory. In probability theory, the birthday paradox or birthday problem considers the probability that some paired people in a set of n randomly chosen of them, will have the same birthday.

How many people should be invited to a party in order to make it likely that there are three people with the same birthday?

Hence we would expect to need 83 or 84 people in the room before having a 50-50 chance of getting three people with the same birthday.

What is the probability of your friend being born in April?

(365/365) * (1/365) = 1/365, or about 0.27\%.

What is the probability of two friends having birthday on same date?

What’s the chance that two people share the same birthday? The first person can be born on any day of the year, this means that the probability is 365/365 = 1. The second person has to be born on the same day as the first and there is a 1/365 chance of that happening.

What is the probability of a hash collision?

As a rule of thumb, a hash function with range of size N can hash on the order of √N values before running into collisions. This means that with a 64-bit hash function, there’s about a 40\% chance of collisions when hashing 232 or about 4 billion items.