Answer: $4.46
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Work Shown:
3 containers = 6.69 dollars
3/3 containers = 6.69/3 dollars .... divide both sides by 3
1 container = 2.23 dollars
2*(1 container) = 2*(2.23 dollars) ... multiply both sides by 2
2 containers = 4.46 dollars
A shortcut is to start with "3 containers = 6.69 dollars" and multiply both sides by 2/3
Each mention of "container" refers to a half-gallon container.