Calculate the costs for food, exhibition materials, and administrative costs for the Open-door day in 2023, given the total cost and the ratio of expenses.

Here are the solutions to the questions:

I. Cost Calculation

a) Find each of these costs for the Open-door day in 2023
The total cost in 2023 was $1,500,000\,\text{FCFA}$. The costs are divided in the ratio 3:6:1 for food, exhibition materials, and administrative costs, respectively.
The sum of the ratio parts is $3 + 6 + 1 = 10$.

Step 1: Calculate the cost of food.

$$\text{Cost of food} = \frac{3}{10} \times 1,500,000\,\text{FCFA}$$ $$\text{Cost of food} = 450,000\,\text{FCFA}$$