The number of cats and dogs the doctor saw is 56.
Ratio expresses the relationship between two values. It shows the frequency that one value is contained another value. The sign of ratio is :.
The equation that can be used to determine the total number of dogs that the doctor saw is:
(ratio of dog / total number of dogs and cats) x total number of animals = number of dogs
5/7 x a = 40
Where a is the total number of dogs and cats
In order to determine the value of a, divide both sides of the equation by 7/5.
40 x 7/5 = 56
To learn more about ratios, please check: https://brainly.com/question/3033738