In a class 28 of students, 5 have a cat and 21 have a dog. There are 4 students who do not have a cat or a dog. What is the probability that a student who has a dog also has a cat?

15 have only a dog

5 have a dog and a cat

9 have only a cat

Step-by-step explanation:

20 + 14 = 34, there there are only 29 students, so 34 - 29 or 5 have both a dog and a cat

15 have only a dog

5 have a dog and a cat

9 have only a cat