Judy pays $29 for 8 gallons of gas and 2 bottles of water. Carmen pays $45 for 12 gallons of gas and 4 bottles of water. How much does one gallon of gas cost? How much does 1 bottle of water cost?

G=gas

w=bottle of water

8g + 2w = 29

12g + 4w = 45

I'm going to use elimination to cancel out the variable w by multiplying the first equation by - 2.

-16g - 4w = - 58

12g + 4w = 45

-4g = - 13

/-4 / - 4

g = 3.25

Now plug it into an equation, any equation.

8 (3.25) + 2w = 29

26 + 2w=29

w=1.5

Now to check, plug it into both equations if you want.

12 (3.25) + 4 (1.5) = 45

39 + 6=45

One bottle of water is $1.50, while one gallon of gas is $3.25.