Ryan earns $5 for each small dog he walks and $8 for each large dog he walks. Today he walked 8 dogs and made a total of $55. How many small dogs did Ryan walk?

Let x be the number of small dogs and y be the number of the large dogs. The equations that best represent the given conditions above are,

x + y = 8

5x + 8y = 55

The values of x and y in the equations are 3 and 5. Thus, Ryan walked 3 small dogs.