Annabelle went to the grocery store and bought bottles of soda and bottles of juice. Each bottle of soda has 30 grams of sugar and each bottle of juice has 10 grams of sugar. Annabelle purchased 3 times as many bottles of juice as bottles of soda and they all collectively contain 120 grams of sugar. Graphically solve a system of equations in order to determine the number of bottles of soda purchased, x and the number of bottles of juice purchased, y.