To find the unit rate (the ratio of earnings per hour), divide the total earnings by the total number of hours worked.
Gloria Trench earned $144 in 8 hours:
\[ \text{Unit rate} = \frac{\text{Total earnings}}{\text{Total hours}} = \frac{144 \text{ dollars}}{8 \text{ hours}} = 18 \text{ dollars per hour} \]
So, the unit rate is \( 18 \) dollars per hour.