Answer (8) Let the 100 things are A1 , A2 ... A100 fixed on circle. If A1 is selected then A2 and A100 cannot any twonon - adjacent of A1 he selected from A3 to A99 . This can be done by
97
C2 - 96 = 4560 ways . Similarly for other two letters also . ∴ Total number of selections = 4560 × 100 = 456000 , but here every thing is counted threetimes. ∴ N =