1. **State the problem:** Valentina's parents buy a 6-day Fun Pass and a 30-dollar arcade pass, spending a total of 129 dollars. We need to find the daily cost of the Fun Pass. 2. **Define variables:** Let $x$ be the daily cost of the Fun Pass. 3. **Write the equation:** The total cost for the Fun Pass is $6x$ (since it's for 6 days). Adding the arcade pass cost, the total is: $$6x + 30 = 129$$ 4. **Solve for $x$:** Subtract 30 from both sides: $$6x = 129 - 30$$ $$6x = 99$$ Divide both sides by 6: $$x = \frac{99}{6}$$ Simplify the fraction: $$x = 16.5$$ 5. **Interpretation:** The daily cost of the Fun Pass is 16.5 dollars. **Final answer:** $16.5$