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Resources & Downloads => Mathematics => Topic started by: Turner on Oct 07, 07:14 AM 2012

Title: Birthdays probability
Post by: Turner on Oct 07, 07:14 AM 2012
I'm reading a book called Taking Chances
Theres a great section on probability on Birthdays.

The question is .....
How many random people would you have to ask their birthday before the probability of 2 people having the same birthday was more favourable than not.

For the purposes of the exercise leap years and seasonal peaks are taken out (more people are born in the summer etc.)

I found the answer a shock...but very interesting

I guessed 183...because its slightly over half the amount of birthdays one can have.

I was sooo wrong.

if anyone bothers to reply...I will reveal the answer and show the maths (math....whatever!)
Turner
Title: Re: Birthdays probability
Post by: Ralph on Oct 07, 08:31 AM 2012
I think it would be around 20 or so.
Title: Re: Birthdays probability
Post by: Turner on Oct 07, 02:11 PM 2012
Yep....23

Title: Re: Birthdays probability
Post by: Ralph on Oct 07, 07:39 PM 2012
And you may think if 23 persons can enter the door and it is a very high probability two have the same birthday, how is the the probability for two numbers to repeat.