One family ordered three burgers and three sodas and their bill was $12. Another family ordered five burgers and three sodas and paid $18. How much did it cost for one burger and one soda

a single burger costs $2, and a single soda costs $1.

Step-by-step explanation:

Lets set up a system of equations, with b for the burgers and s for the sodas

3b + 3s = 12

5b + 3s = 18

rewriting to switch the order of the equations

5b + 3s = 18

3b + 3s = 12

Then, we need to eliminate one variable to make it easier for us to find both, let's eliminate s by multiplying the entire bottom equation by - 1

5b + 3s = 18

-3b - 3s = - 12

adding the two together, we get

2b = 6

divide by 2 on both sides and we get

b = 3

THen, we take that value and plug it in to either of our first two equations (I'm using the first equation), and we get

3 * 3 + 3s = 12

multiply

9 + 3s = 12

subtract 9 from both sides

3 s = 3

divide both sides by 3

s = 1

this means that a single burger costs $2, and a single soda costs $1.