Wrapping paper rolls are sold in packages of 2, 4, or 6. The following prices apply to the packages:

Package of 2 rolls ------- $1.50

Package of 4 rolls ------- $2.50

Package of 6 rolls ------- $3.50

Lisa needs to buy exactly 12 rolls of wrapping paper for a service project.

Below are a few of the possible combinations. Select the value that correctly represents the missing number in the combinations listed on the table.