Hey, need help with this:

(c) An urn contains ve green balls and seven blue balls. A ball is selected at random and not replaced. Another ball is selected. (i) What is the probability that the rst ball is blue ? (ii) What is the probability that the second ball is blue ? (iii) What is the probability that both balls are blue ? (iv) Given the second ball was blue, What is the probability that both balls were blue