Exercise 3: There are two boxes of equal size, one red and one yellow. The red box contains 8 white and 4 black tiles and the yellow box contains 3 white and 5 black tiles. A regular die is rolled if it rolls a 1 or 5 a token is taken from the yellow box and placed in the red box and then a token is taken from the red box; if another number appears, a chip is taken from the red box and placed in the yellow box and then a chip is drawn from the yellow box. What is the probability that both tiles are black?