1. The problem asks for the percentage of Claudia's total yearly work time spent on the project "Customer Survey" given she spends $x$ percent of her monthly work time on the project for $a$ months and $y$ percent for $b$ months. 2. Since the total work time is the same each month and absence/holidays are ignored, the total yearly percentage is a weighted average of the monthly percentages. 3. The formula for the weighted average percentage is: $$\frac{a \cdot x + b \cdot y}{a + b}$$ 4. Given that $a + b = 12$ months in a year, substitute this into the denominator: $$\frac{a \cdot x + b \cdot y}{12}$$ 5. This formula gives the average percentage of work time spent on the project over the entire year. 6. The other options involving $100$ in the denominator or products $a \cdot b$ and $x \cdot y$ are incorrect because: - Dividing by 100 would convert a percentage to a fraction, but here we want the weighted average percentage. - Multiplying $a \cdot b$ or $x \cdot y$ does not represent a weighted average. 7. Therefore, the correct answer is: $$\frac{a \cdot x + b \cdot y}{12} \text{ percent}$$