Answer:3
Step-by-step explanation: By the information we have been given we know that 4 students have cats and dogs because if you subtract the 6 students that have only cats from the 10 students who have cats you are left with 4. Then you subtract the 4 who have cats and dogs from the amount of students who have dogs and you get the number of students who have only dogs, which is 5 students. So we know 4 students have cats and dogs, 5 students have only dogs, and 6 students have only cats. 4+5+6=15 out of the 18 students have pets so 3 students do NOT have cats or dogs.