In the houses of María, Juana and Paula there are a total of 16 animals, among which there are 3 dogs, twice as many cats, canaries and parrots. At Juana's house they can't see the dogs or the parrots, but they have 4 cats and two canaries. In Paula's house there is only one dog and two cats and finally in Maria's house they have 3 canaries with other animals.
What animals does Maria have in her house?
We can make a table with the information to complete it, since in reality it is about that among all the animals they add the indicated amount and that the total of animals that live in a house coincide with what they tell us.
Let's put the information we have in a table:
Now, we can find the totals of animals from the houses of Paula and Juana, as well as the dogs and cats that are in María's house and the totals of the Canaries. To finish, we need the data we just got to find out the total number of animals in Maria's house (those that are missing in the others to reach 16) and hence the number of parrots they have in Maria's house. Or, the total number of parrots, which lets us know how many are in Maria's house (all, since none of the others have parrots).
Definitely, María has 2 dogs, 2 parrots and 3 canaries at home.