A pouch contains 59 green beads 78 red beads and 50 yellow beads How many blue beads should be added so that the probability of drawing a red bead is one third?

Answer 1

For the probability of drawing a red bead to be one third then one third of the bead would need to be red. The number of red beads is 78 so twice as many should be 'not red' (156), at present the 'not red' beads (yellow and green) total 109, so to make the number up to the required 156 a further 47 beads need to be added so the number of blue beads needed is 47.