7. If you are randomly sampling one at a time without replacement from a bag that contains eight blue marbles, seven red marbles, and five green marbles, what is the probability of obtaining:

A blue marble in one draw from the bag?

Three blue marbles in three draws from the bag?

A red, a green, and a blue marble in that order in three draws from the bag?

At least two red marbles in three draws from the bag?

I need it in the following format:

P(1 blue marble) 8/20= .4000

P(3 marbles, 3 draws)-= 2/5^2/5^2/5= .0640

etc.