Answer:
A soda costed $3.50.
Step-by-step explanation:
Step 1) We know that a slice of pizza and a soda costs $9 (from Kate's order). With a burger added (Billy's order) it would cost $13.50.
So a burger would cost $4.50:
[tex]13.50-9=4.50[/tex]
Step 2) We also know a burger and a soda costs $8. So we subtract the cost of the burger from Louis' order to find the cost of the soda:
[tex]8-4.50=3.50[/tex]
Cost of soda: [tex]\$3.50[/tex]
