1. **State the problem:** A gardening service charges a base fee of 45 plus 16 for each hour of work. The total cost is 253. We need to find the number of hours $h$ worked. 2. **Write the formula:** Total cost $C$ is given by $$C = \text{base fee} + (\text{hourly rate} \times h)$$ Here, $$253 = 45 + 16h$$ 3. **Isolate $h$:** Subtract 45 from both sides: $$253 - 45 = 16h$$ $$208 = 16h$$ 4. **Solve for $h$:** Divide both sides by 16: $$h = \frac{208}{16}$$ $$h = 13$$ 5. **Interpretation:** The gardener worked 13 hours on the job. **Final answer:** $h = 13$ hours.