Answer: it will take 6 months for her collection to have 18 pucks.
Step-by-step explanation:
Let x represent the number of months it will take for her collection to have 18 pucks.
She has 12 pucks already in her collection. She has a friend that works at the stadium that can get her 3 new pucks each month. This means that the number of pucks that she would have after x months is expressed as