Answer: 12 different combinations were possible.
Explanation:
Given: At LaMar’s birthday party, his parents served slices of plain, sausage, or pepperoni pizza.
i.e. The number of types of pizza = 3
They also served cups of milk, orange juice, apple juice, or lemonade.
i.e. The number of types of drinks = 4
Now, if each guest at the party chose one slice of pizza and one type of drink, then the number of different possible combinations are :

Hence, there were 12 different combinations .