We know that
• 11 students own a cat.
,
• 12 students own a dog.
,
• 6 students own both a cat and a dog.
,
• 3 students own neither.
First, let's draw a Venn diagram to visualize the problem.
First, we have to fund the total number of students inside the sets Cat and Dog. We need to subtract the number 6 once, otherwise, we'll count it twice.
[tex]11+12-6=17[/tex]
Then, we include the students that own neither.
[tex]17+3=20_{}[/tex]
Therefore, the total number of students is 20.
