Answer:
564,480
Step-by-step explanation:
The appliocation of factorial n! = n(n-1)(n-2)(n-3).....
Arrangement when french and English delegates are to seat together ;
since we have 10 delegates, Freench and english will be treated as 1 delegates as such we have 9groups. The number of ways of arranging 9groups = 9! and if the french and English are to be treated as a group = 2!
Hence, number of ways of arrangement = 9! x 2! = 725,760
In this case, English and french are to be seated next to each other while russia and US delegates are not to seat nect to each other ; both groups will be treated as 2 as such we have 8groups, the number of ways of arranging 8groups = 8!
french and english together = 2!
Russia and US together = 2!
The number of ways of arrangement = 8! x 2! x 2! = 161,280
hence the number of ways of arranging 10 delegates if french and english are to be seated next to each other and Russia and US are not to be seated next to each other;
N = 725,760 - 161,280 = 564,480