To solve this problem, we need to model the rates at which Tabitha and her coworker produce units.
Let \( x \) be the rate (in units per hour) at which the coworker works.
Tabitha works at a rate of: \[ \frac{1 \text{ unit}}{10 \text{ hours}} = \frac{1}{10} \text{ units/hour} \]
When working together, they produce 1 unit in 5.24 hours, so their combined rate is: \[ \frac{1 \text{ unit}}{5.24 \text{ hours}} = \frac{1}{5.24} \text{ units/hour} \]
The formula for their combined rates can be expressed as: \[ \text{Rate of Tabitha} + \text{Rate of Coworker} = \text{Combined Rate} \] or more specifically: \[ \frac{1}{10} + \frac{1}{x} = \frac{1}{5.24} \]
This matches option (2). Thus, the correct rational equation that could determine the rate at which the coworker produces units is:
2. \( \frac{1}{10} + \frac{1}{x} = \frac{1}{5.24} \)