1. **State the problem:** We want to find the number of hours $h$ for which renting a scooter by the day is cheaper than renting by the hour. 2. **Define the costs:** - Hourly rental cost: $20h + 10$ (including $10 insurance) - Daily rental cost: $80 + 10$ (including $10 insurance) 3. **Set up the inequality:** We want the daily cost to be less than the hourly cost: $$80 + 10 < 20h + 10$$ 4. **Simplify the inequality:** $$90 < 20h + 10$$ Subtract 10 from both sides: $$90 - 10 < 20h + \cancel{10} - \cancel{10}$$ $$80 < 20h$$ 5. **Solve for $h$:** Divide both sides by 20: $$\frac{80}{\cancel{20}} < \frac{20h}{\cancel{20}}$$ $$4 < h$$ 6. **Interpretation:** Renting by the day is cheaper when the number of hours $h$ is greater than 4. **Final answer:** It is cheaper to rent by the day if you rent for more than 4 hours.