A Starbucks store sells coffee in three sizes: a12-oz tall, a 16-oz grande, and a 20-oz venti. A tall coffee sells for $1.75, a grande coffee for 1.95, and a venti coffee for 2.25. One morning, brandie served 50'coffees for a total of 98.70. She made the coffee in 80 oz batches and used exactly 10 of the batches during the morning. How many of each size did she sell? Write the three equations you would use to solve. Using Gauss-Jordan elimination, solve the system.