Answer:
There are 436937109262510348800 ways to selected 12 countries.
Step-by-step explanation:
Let the countries selected from the block of 45. For
there are 45 options of countries to select. For
there are 44 options of countries to select because there can be no repeated countries. With the same reasoning, for
there are 43 options, for
there are 42 options and for
there are 41 options.
Let the countries selected from the block of 57 countries. For
there are 57 options of countries to select. For
there are 56 options of countries to select because there can be no repeated countries. With the same reasoning, for
there are 55 options and for
there are 54 options.
Let the countries selected from the block of 69 remain countries. For
there are 69 options of countries to select. For
there are 68 options of countries to select because there can be no repeated countries and for
there are 67 options.
For find the total of options o ways to select 12 countries we multiply the above options.