The Green Goober, a wildly unpopular superhero, mixes $3$ liters of yellow paint with $5$ liters of blue paint to make $8$ liters of special green paint for his costume.
**Write an equation that relates the amounts (in liters) of yellow paint $(y)$ and blue paint $(b)$ needed to make the Green Goober's special green paint.**
[[☃ expression 1]]