need ans asap pls:

A box contains six bags of Haribo Starmix and two bags of Haribo Goldbear. Justin chooses five bags at random without replacement. Let S be a discrete random variable counting the number of Starmix bags he ends up with and G a discrete random variable counting the number of Goldbear bags he ends up with.

a) Find the probability mass function of G. Work out at least one of the probability values as a simplified fraction.

b) Without doing any more calculations, write down the probability mass function of S and briefly explain.