Permutation - Two couple at the round table question

[@yingshiantay157]

hi sir, for question b) is it mean that the two couple must sit seperately?
if for 480 ways, then it include the two couples to sit seperately and next to each other right?
so to get the number of ways the two couples want to sit seperately, is it need to minus 192 ways, like 480 - 192 = 288 ways? am i right?
hope for explaination, tq

[@twinkle6718]

yea seems like 480 ways include all types of ways to sit which is sit separately or sit next to each others.😊

[@kahloktai1185]

Why the round table formula must minus 1?

[@claireli88]

You need to fix one position so that the remaining objects can be arranged around it.

[@zhezhezhe4989]

first choice of sitting not considering