Question 1092064
Since the people of the same nationality will be sitting together, this problem is identical to one where there is one person of each of 4 different nationalities and we need to seat them into 4 seats.  Let's label the nationalities A,B,C,D

The seats can be drawn   __1__|__2__|__3__|__4__    (if you must, you can think of each numbered seat as a GROUP of seats which will hold all the people of a given nationality).

There are 4 choices (A,B,C,D) to sit in seat 1
That leaves 3 choices for seat 2
2 choices for seat 3
1 choice for seat 4
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We must <b>multiply</b> the above choices, because, for example, after choosing who sits in seat 1, the other 3 seats are chosen independently (say B sits in seat 1, then A,C,and D can shuffle themselves in the remaining 3 seats any way they want).    Mathematically, it is written 4! =  4*3*2*1 = {{{ highlight(24) }}}