Solve the following recurrence relations (provide a closed form solution):
(a) an = −3an−1, a0 = 4
(b) an = an−1 + 1, a0 = 12
(c) an = 12an−1 + 2, a0 = −1

Fracisco's game involves 3 green, 2 yellow, 4 red, and 3 black marbles. if he randomly draws three marbles from the bag, without replacement, what is the probability that he will draw yellow, and then red, and then black? a)1/192 b)1/72 c)3/220 d)1/55