/sci/ - Science & Math

>>11631174

Because of pic related. We get P(B∩A) + P(B∩¬A).

Here is a probability problem i can't seems to resolve it's a pretty basic one but i'm stuck.
It goes like this, In the basement of a family residence, two sisters discover a vinyl collection. They find 8 vinyl, 2 jazz records and 6 rock records. They take turns choosing a record at random and they listen to some extracts. The youngest starts
to choose. Calculate the probability that the eldest is the one who will get the first record of
jazz.
My question is how to resolve it, and if possible to explain to me how to resolve these kind of problems that goes in successive turn (it could be any other situation of X goes first, what are the chances of X or Y to get Z first or second).