SOLUTION: I have six grandchildren, the youngest born on August 10, 2009. My oldest grandchild was born on August 10, 1996 and her younger sister was born on August 10, 2000. What is the

Question 212074: I have six grandchildren, the youngest born on August 10, 2009. My oldest grandchild was born on August 10, 1996 and her younger sister was born on August 10, 2000. What is the probability of having 3 of 6 grandchildren share the same birthday?
Jack Frost, MD
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
P(having a certain birthdate) = 1/365
Binomial Problem: 3 of 6 have the same birthdate.
P(3 of 6) = 6C3(1/365)^3*(364/365)^3
= 20(365)^(-3)(0.997)^(3)
---
= 0.00000040792...
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Cheers,
Stan H.
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