To use a ratio, is like to use a fraction. What you need to do is add the two numbers in the ratio together, to get 13 (6+7). Now we know that for every 13 animals, 6 are cats and 7 are dogs. In 65 there are 5 13s (because 65/13 is 5), therefor, to get the number of cats, we need to times 6 by 5. This gets us 30. Similarly to get the number of dogs we do 5x7=35. Just to check, we can add 30 (number of cats) to 35 (number of dogs) which is 65, which is the number of cats and dogs given by the question. Therefor our answers are right! :)
