Final answer:
To find the number of cats, divide the number of dogs by the ratio of dogs to cats. In this case, there are 3 cats in the apartment complex.
Step-by-step explanation:
To find the number of cats in the apartment complex, we need to understand the ratio between dogs and cats. From the given model, we can see that the number of dogs is 4 times the number of cats.
So, if there are 12 dogs, we can calculate the number of cats by dividing the number of dogs by the ratio. In this case, 12 divided by 4 equals 3. Therefore, there are 3 cats in the apartment complex.
The correct answer is option a) 12.