Answer: There are 2346953264 ways to do so.
Step-by-step explanation:
Since we have given that
Total number of selected countries = 12
Number of selected countries from a block of 45 = 3
Number of selected countries from a block of 57 = 4
So, remaining number of selected countries from a block of 69.
So, 12-(3+4)=12-7=5
Now, we need to find the number of ways, so we will use "Combination" to select that number of countries.
So, it becomes.
Hence, there are 2346953264 ways to do so.