Ethan and his children went into a movie theater where they sell drinks for $6 each and pretzels for $5 each. Ethan has $100 to spend and must buy at least 18 drinks and pretzels altogether. Also, he must buy no less than 16 pretzels. If xx represents the number of drinks purchased and yy represents the number of pretzels purchased, write and solve a system of inequalities graphically and determine one possible solution.