Its not just you. So, don't worry....
Let me first share with you a couple of formulae related to circular permutations. Digest them with logic & you will start getting a grip on these kind of problems.
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Number of circular permutations = n!/((n-r)!*L)
n --> number of objects in the source group
r --> number of objects selected
L --> number of possible locations for the first object placed.
So, based on information we have from the question, n=5 (source group), r=5 (selected) & L=5 (the number of locations for the first person to sit).
5!/((5-5)!*5) ==> 5!/5 ==> 4*3*2 ==> 24ways
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As Neo2000 mentioned, the number of ways the 5 kights can be seated at the round table is (n-1)!. This formula is derived from the above when n=r=L
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The above conditions are when there is a difference in clockwise & anti-clockwise arrangement.
When there is no difference in clockwise & anti-clockwise arrangement, the formula we should use is (n-1)!/2.
Hope this helps.
