Answer the question of tourism

Step 1: Percentage increase in tourism revenue from 2020 to 2021.

Formula:
$\text{Percentage increase} = \frac{revenue_{2021} - revenue_{2020}}{revenue_{2020}} \times 100\%$

Substitute revenue$_{2020} = 1200$ million dollars, revenue$_{2021} = 1500$ million dollars:
$\frac{1500 - 1200}{1200} \times 100\% = \frac{300}{1200} \times 100\% = 0.25 \times 100\% = 25\%$

25%

Step 2: Total tourism revenue from 2020 to 2022.

Formula:
$\text{Total revenue} = revenue_{2020} + revenue_{2021} + revenue_{2022}$

Substitute revenue$_{2020} = 1200$ million dollars, revenue$_{2021} = 1500$ million dollars, revenue$_{2022} = 1800$ million dollars:
$1200 + 1500 + 1800 = 4500$ million dollars

4500 million dollars

Step 3: Average annual tourism revenue from 2020 to 2022.

Formula:
$\text{Average revenue} = \frac{total revenue}{3}$

Substitute total revenue = 4500 million dollars:
$\frac{4500}{3} = 1500$ million dollars

1500 million dollars