19) 3/8
24 - 15 = 9
9/24 = 3/8
20) 3/28
8 total people running. We want to know the probability that both the president and vice-president are girls, so we have to assume that the president is a girl first.
3/8 x 2/7 = 6/56 = 3/28
21) Travis should play the game where he has to pick either an A or B out of a hat which contains letters A, B, C, D, and E. The probability of him drawing an A or B and winning is 2/5, or 0.4. If he plays the other game, then the probability of him winning is only 1/3, or 0.33.
Probability of rolling a 2 or 3 on a die = 2/6 = 1/3 (0.33)
Probability of picking an A or B = 2/5 (0.4)
