12 Oreo cookies
Alexane has 12 oreo cookies of which 9 are the regular type and 3 are golden type.
She wants to share her oreos with her 3 friends Jose, Amy, and Camille.
She puts the 12 oreos in a brown bag and she and her 3 friends each randomly choose 3 oreos.
What is the probability that exactly one of them ends up with all 3 golden oreos?
If the probability can be expressed as \( \dfrac ab\), where \(a\) and \(b\) are coprime positive integers, find \(a+b\).