Emilia and Jennifer are making charm bracelets to sell at a Renaissance festival. They have used their savings to cover the costs of the materials, but hope to make a profit after selling the bracelets. They'll make $15 in profit if they sell 10 bracelets. They'll make $45 if they sell 15 bracelets.
In this relationship, x represents the number of bracelets they sell, and y represents their profit (in dollars).