To calculate the unit cost, you need to determine the cost per hour. In this case, you have a total of 2.5 hours at a total cost of $8.
The formula for unit cost is:
\[ \text{Unit Cost} = \frac{\text{Total Cost}}{\text{Total Hours}} \]
Plugging in the values:
\[ \text{Unit Cost} = \frac{8}{2.5} = 3.2 \]
So, the unit cost is $3.20 per hour.