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The question reads thus: "A large firm employs 4250 employees. One person is chosen at random. What is the probability that the person's birthday is on Monday in the year 2008."

Can someone please tell me whether this problem is:

  1. To be done using simple probability (considering that the data 4250 employees and the year 2008 is defunct data)?

Or

  1. To be done with the principle of conditional probability? (If this is the answer, please solve it for me)
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    Why would the number of employees or the year in question be defunct data? One thing worth mentioning is that there is no way to solve this problem without further information. We need to know something about the distribution of birthdays of the employees. From a realistic standpoint, I think the probability is almost zero. Child labor laws usually stop children of 8 or 9 from working in large firms... at least in the US. Theoretically an old looking 9 year old could forge documents and work for a large firm, but that seems very unlikely. – 2017-02-05
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    @SeanEnglish Often times, people refer to any occurrence of the day and month of their birth regardless of year as their birthday (*so long as it occurs during their lifetime*), not just the actual occasion of their birth. Someone whose $50$'th birthday occurs on a monday in 2008 would still be described as having a birthday on monday in 2008 (*compare to the phrase "was born on a monday in 2008"*). The end result is still though that there isn't enough information to solve. (*though one might expect it to be near $1/7$*) – 2017-02-05
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    @JMoravitz Yeah... I believe that the question means the occurrences of the birthday on a Monday in 2008. – 2017-02-06

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This should be a condition of simple probability P = no of Mondays in 2008/366 The total number of employees should be insignificant here

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    That is assuming that each calendar day of the year in 2008 is equally likely to be someone's birthday (*feb 29 is in practice less likely than other days due to leap year rules, not to mention certain seasons often affecting people's mating habits*). This is often not a safe assumption to make since in reality [fall birthdays seem to be more common](http://www.panix.com/~murphy/bday.html) across the population, but even worse perhaps this company has some bizarre tendency to hire people with specific birthdays that we haven't yet been told about. Final result: not enough information. – 2017-02-05
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    Given the limited information the next assumption would be to take simple probability – 2017-02-05
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    Can you further justify your answer? I want to understand this better. – 2017-02-06