Probability
posted by Tom on .
An urn contains 7 red marbles labeled {1,2,3,4,5,6,7} and 5 green marbles labeled {1,2,3,4,5}. Four marbles are pulled out at once. What is the probability that
A. All four marbles are red?
B. More of the marbles are green than red?
C. Both red and green marbles are present?
D. Two of the marbles chosen are both labeled "5"?

I've tried but i need help =/

You are randomly drawing marbles from a bag containing 4 blue and 2 green marbles, replacing the marbles between draws. Which of the following will give the probability of drawing a blue marble on both your first and second draws?