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?
ryan walked small dogs.

Let L and S be the number of large and small dogs respectively.

L+S=8 so we can say L=8-S

5S+8L=55, using L found above in this equation yields:

5S+8(8-S)=55

5S+64-8S=55

-3S+64=55

-3S=-9

S=3, since L=8-S

L=5

So Ryan walked 3 small dogs and 5 large dogs.