Okay, here are my calculations.

Let us view the problem as this: Experiment: there are 23 people, each one is choosing 1 day for his birthday, and trying not to choose it so that it's same as others.

So the 1st person will easily choose any day according to his choice.

This leaves 364 days to the second person, so the second person will choose such day with probability 364/365.

Same with the third guy, but now he should not choose the day same as 1st as well as 2nd person and hence he has 363 days and probability= 363/365.

So the probability of the experiment is 1.(364/365).(363/365)....(343/365) which is approximately 50%.

I hope this helps.

Okay, here are my calculations.

Let us view the problem as this: Experiment: there are 23 people, each one is choosing 1 day for his birthday, and trying not to choose it so that it's same as others.

So the 1st person will easily choose any day according to his choice.

This leaves 364 days to the second person, so the second person will choose such day with probability 364/365.

Same with the third guy, but now he should not choose the day same as 1st as well as 2nd person and hence he has 363 days and probability= 363/365.

So the probability of the experiment is 1.(364/365).(363/365)....(343/365) which is approximately 50%.

I hope this helps.

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