[" Six persons "A,B,C,D,E" and "F" are to be seated at a circular table.The number of ways this "],[" done if A must have either "B" or "C" on his right and "B" must have either "C" or "D" on his right is this can be "],[" The number of permutations which can be formed out of the letters of the word' SERIES - laking "],[" etters together is "],[" I box contains "6" balls which may be all of different colours or three each of two colors or two each "],[" retisch in colours.The number of ways of selecting "3" balls from the bolut of the "]