The owner of the restaurant pays $11.55 for the dinner and charges $20.55 for it.
To determine the percent markup, you have to calculate the percentage of increase.
-First, calculate the difference between the sale price and the buy price:
![20.55-11.55=9](https://img.qammunity.org/2023/formulas/mathematics/college/a0bhtib6hlxlwwh9udtb9a874cfstvihqb.png)
-Second, divide the result by buy value and multiply by 100:
![(9)/(11.55)\cdot100=77.92](https://img.qammunity.org/2023/formulas/mathematics/college/yqvuzkczj7xqmiba45kef8rc5aagqay3b4.png)
The markup percent is 77.92%