19. There are 12 boys and 18 girls in Mr. Spano's math class. If he randomly calls on three students for answers to an assignment, what is the probability that all three are girls? Assume he does not call on the same student more than once. 20. Alexis is rearranging the letters of the word DINOSAUR. What is the probability that the first three letters she chooses are vowels? Use for questions 21-24: Out of 50 students, 24 are taking art and 30 are taking music. Sixteen of the students are taking both art and music. If two different students from this group are chosen at random, find each probability. 21. Both students take art. 22. Both students take both art and music. 23. Both students take music, but not art. 24. Neither student takes music.