a lot of Thank you ...
As to the first: look at the probabilities of the complements:
P(U\E) = ???
P(U\F) = ???
and then look at P(U\(E n F)).
(where U is the "universe", i.e., all events).
As to the second: does it really matter which birthday person1 has? So, say it's January 13. Then look at the birthday of person2.
Refer to the link below, you will be able to solve the 2nd problem.
Birthday problem - Wikipedia, the free encyclopedia
we dont know what day is for the first person, so we consider it as 1st january. and now we say, the probability of the second person having the same birthday is :
P= 1 / 366
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is this True???? thank you