As a young girl, Adriana enjoyed watching her father make things in his woodworking shop. Now that she's grown up, Adriana builds wooden furniture for a living. Her most popular product is a cedar porch swing. There is a proportional relationship between the time (in days) Adriana spends making porch swings, x, and the number of swings she builds, y. It takes Adriana 5 days to build 1 swing. Write the equation for the relationship between x and y.