Question

Bella has 7 green beads, 10 yellow beads and 3 white beads in a pouch. two beads are drawn without replacement from the pouch. what is the probability that both of the beads are yellow? write your answer as a fraction.

Answer 1

Total number of beads 7+10+3=20. We are looking at the combination of 20 events. Applying the probability formula $p= \frac{m}{n}$, the total number of possible outcomes is $C _{20}^{2}$ and the possible outcomes is $C_{10} ^{2}$. Then, the probability is $p= \frac{C_{10} ^{2} }{C_{20} ^{2} } = \frac{9}{38} = 0.236842$