A box contains only wood (w), red glass (r), and blue glass (b) marbles. The number of glass beads is 4 times the number of wood beads. If one bead is to be chosen at random, the probability of a red glass bead is 3 times the probability of a blue glass bead. There are 12 red glass beads in the box. How many total beads are in the box?
12=3b, so b=4