You purchase muffins for you and your coworkers. You buy a total of 15 muffins for $27.50. Each blueberry (x) costs $1.50, each chocolate chip (y) costs $2, and each banana nut (z) costs $2.50. You know that you will need twice as many blueberry as chocolate chip muffins. How many of each type of muffin did you buy? The system of equations is \begin{cases} x+y+z=15 \\ 1.5x+2y+2.5z=27.50 \\ x=2y \end{cases}{ x + y + z = 15 1.5 x + 2 y + 2.5 z = 27.50 x = 2 y Using the elimination method, group the first two equations together and eliminate the x. What is the resulting equation containing only y and z?