Prob question?

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In a group of 9 persons what is the probability that 3 persons have
the same b'day in a week?please provide the procedure also..

2007-01-07 23:06:03 · 1 answers · asked by Red Falcon 1 in Science & Mathematics ➔ Mathematics

1 answers

This is a binomial distribution problem.
Let p = 1/52 be the probability of having a birthday this week.

(9C3)[(1/52)^3][(51/52)^6] is the probability of 3 out of 9 people having birthday this week. Here 9C3 equals 9!/[6!3!]

The above is then multiplied by 52 to account for ANY week.

2007-01-08 00:01:04 · answer #1 · answered by fcas80 7 · 0⤊ 0⤋