Kindly provide a step by step explanation and answer to this, thanks

(Example) A package, say P1, of 24 balls, con- tains 8 green, 8 white, and 8 purple balls. A Package, say P2, of 24 balls contains 6 are green, 6 white and 12 purple balls. One of the two packages is selected at random. (b) If 3 balls from this package were selected, they are 1 green, 1 white, and 1 purple ball. Compute the conditional probability that pack age P2 was selected