Gitta is planning a birthday party. She has an $80 budget. Pizzas cost $5 each, 2-liter bottles of soda cost $3 each, and delivery is charged at a flat rate of $5. If she buys 12 pizzas, how many bottles of soda can she buy?

C≥5+3s+5p, we are told that she has $80 and orders 12 pizzas so

80≥5+3s+5 (12) perform indicated multiplication on right side

80≥5+3s+60 combine like terms on right side

80≥3s+65 subtract 65 from both sides

15≥3s divide both sides by 3

s≤5

So she can buy at most, 3 bottles of soda.