Microsoft Interview Question: Consider n people with random... | Glassdoor

Interview Question

Software Development Engineer II Interview Seattle, WA

Consider n people with random birthdays. How large does n

  need to be before there is at least a 50% chance that two people have the same birthday?

Interview Answer

2 Answers


I'll say 365

there are 365 possible birthdays, there is 1/365 chance for a person's birthday falling on a specific day. You need (1/2 of 365)*2 to improve the chance to 50% for two peoples' birthday falling on the same date.

kb on Jun 3, 2012

No. There is no N In your formula. That probability depends on N.

Anonymous on Jun 12, 2012

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