Answer:
2.75; 9.50 + 4x = 20.50
Explanation:
First, lets write an equations: 9.50 + 4x = 20.50. Subtract 9.50 from 20.50, giving us: 4x = 11. Then divide 11 by 4, giving us x = 2.75. Each drink cost $2.75. To check this, plug in 2.75 for x in the original equations and you will get 20.50.