Mariam is going to see a movie and is taking her 3 kids. Each movie ticket costs $12 and there are an assortment of snacks available to purchase for $3 each. How much total money would Mariam have to pay for her family if she were to buy 6 snacks for everybody to share? How much would Mariam have to pay if she bought x snacks for everybody to share?

Cost for 6 snacks:
Cost for xx snacks: