Bubble Company produces a variety of bottles from recycled plastic. The company has one particular machine on which it can produce either of two types of water bottles, 1-liter bottles or 1/2-liter bottles. Sales demand for both products is such that the machine could operate at full capacity on either of the products, and Bubble can sell all output at current prices. One unit of the 1/2-liter product requires one hour of machine time per unit of output, and one unit of the 1-liter bottle requires two hours of machine time. Each "unit" is a box that contains 150 bottles.
Following are the costs per unit for the bottles:

Per Unit (150 bottles in a unit)
1/2-Liter Bottles 1-Liter Bottles

Selling price $23 $37
Costs
Materials $6 $9
Labor 1 1
Machine maintenance-
and depreciation(a)ᵃ 6 12
Allocated portion of fixed-
factory costs(b)ᵇ 3 3
Total cost per unit $16 $25
Gross margin per unit $7 $12

a. This item is a variable cost because it is based on machine usage.
b. This item is a fixed cost because it is unaffected by the usage of the machine.

All other costs are the same whether Bubble produces 1-liter bottles, 1/2-liter bottles, or both, so you may ignore them.
Required:
Calculate the contribution margin per hour of machine time for the two products. (Round your answers to 2 decimal places.)