# How many people must be there in a room to make the probability 50% that at least two people in the room have same birthday?

Table of Contents

## How many people must be there in a room to make the probability 50% that at least two people in the room have same birthday?

23 people

## How do you calculate combinations?

The formula for combinations is generally n! / (r! (n — r)!), where n is the total number of possibilities to start and r is the number of selections made. In our example, we have 52 cards; therefore, n = 52. We want to select 13 cards, so r = 13.

## What is the probability that 3 persons have same birthday?

approximately 0.6400

## What is the maximum number of people in a gathering such that the probability of two people having the same birthday does not exceed 60?

This is known as the birthday paradox. Don’t believe it’s true? You can test it and see mathematical probability in action! The birthday paradox, also known as the birthday problem, states that in a random group of 23 people, there is about a 50 percent chance that two people have the same birthday.

## What is the most common birthday?

September 9th

## What is the least common birthday?

This Is the Least Common Birthday in the U.S. (No, It’s Not Leap Day)

- February 29.
- July 5.
- May 26.
- December 31.
- April 13.
- December 23.
- April 1.
- November 28.

## Is there a day no one was born?

December 6th is a special day at Who2: it’s the only day of the year on which nobody in our database was born. That’s 2843 famous people (and counting) and none of them born on December 6th.

## Does 365 billion have 7 birthdays?

In support of there being over 7.5 billion birthdays, one for each person in the world, Lisa Leggett, Area Coordinator for MLKCC, explained that everyone has their own birthday “because everyone’s an individual.” She brought up the point about the individuality of the human species being the factor that causes the word …

## What happens when a baby is born on February 29?

People born on a leap year day — February 29 — are often called “leaplings” or “leapers.” But instead of waiting every four years to celebrate their birthdays, most blow out their candles on February 28 or March 1. “I always celebrate on February 28 — my birthday isn’t in March!” my friend Sara says.

## What is the rarest birthday?

This Is the Least Common Birthday in the U.S. (No, It’s Not Leap…

- November 23.
- November 27.
- December 26. white hands opening ribbon on gift wrapped present.
- January 2. Candles on Birthday Cakes.
- July 4. fourth of july party.
- December 24. christmas dinner.
- January 1. girl on her 18th birthday.
- December 25. Average number of births per year: 6,574.

## How many leap years do 400 years have?

97 leap years

## What is the maximum gap between two leap years?

The next leap year comes in 1904 (1900 is not a leap year). Therefore, The maximum gap between two successive leap year is 8 years.

## How many leap years do 300 years have?

72 leap years

## How many odd days are in 75 years?

Answer: 1776 to 15.06. 1776) Counting of odd days: No of odd days in 1600 years = 0 No of odd days in 100 years = 5 75 years = 18 leap years + 57 ordinary years = 18*2 + 57*1 = 36 + 57 = 93 odd days = 13 weeks + 2 odd days = 2 odd days ∴ 1775 years have (0+5+2) = 7 odd days = 0 odd days.

## How do you find a leap year or ordinary year in 75 years?

For 1401–1500 there will be 24 leap years and 76 ordinary years. How? 1404, 1408, 1412, ,1496 as you can see the leap years are multiples of 4 but the year 1500 should be divisible by 400 not 4 so it is not a leap year. For 1501–1600 there will be 25 leap years and 75 ordinary years.

## How many odd days are there in 1900 days?

Solution: You know that in 1600 years, there will be 0 odd days. And in the next 300 years, there will be 1 odd day. From 1901 to 1978 we have 19 leap years and 59 non-leap years. So, the total number of odd days up to 31st Dec.

## Why does 1600 have 0 odd days?

In 400 years there would be 100 leap years, but 3 of them are suppressed. An ordinary year has one “odd day”, and a leap year has an extra “odd day”. Therefore there are 497 odd days in 400 years, which is divisible by 7. A fortiori there remains no “odd day” in 1600 years.

## Why are there no odd days for 400 years?

The number of odd days in 400 years will be ( 5 x 4 + 1) because 400 is itself a leap year and that is why it has one odd day extra. Thus odd days in 400 will be 0. This is same for every year which is a multiple of 100 and 400. Thus 1200 will also have odd days.

## How many odd days are there in 2000 days?

Number of odd days in 2000 = 0. (When 11 is divided by 7, it gives 4 as the remainder.) 31 + 14 = 45 days ⇒ (6 weeks + 3 days) = 3 odd days. ∴ Total numbers of odd days = (0 + 4 + 3) = 7 odd days.

## How many odd days in 700 years has?

In 400 years it become 3 odd days. In 500 years, it become 2 0dd days. In 600 years, there is 1 odd day and in 700 years,there is no odd days..

## How many odd days are there in 1000 days?

6 odd days

## What Cannot be the last day of a century?

Since the order is continually kept in successive cycles, we see that the last day of a century cannot be Tuesday, Thursday or Saturday.

## What is the last day of Century?

400 years contain 0 odd day. Last day of 4th century is Sunday. This cycle is repeated. Last day of a century cannot be Tuesday or Thursday or Saturday.

## How many odd days are there in 500 years?

5 Odd Days

## How many odd days are in 400 years?

0 odd days