Identical twins are of same sex. For fraternal twins have $50$ - $50$ chance of same sex. Given that probability of fraternal twin is $1/3$ and identical twin is $2/3$. In a certain event Find probability that twins are identical, given that they are of same sex.
This problem came in my final exam, I used conditional probability to solve it but couldn't and left it. I am curious whats the answer and how to solve it. I have tried at home but dont know how do I do it. Any hint or guide will be useful