The 11 number of arrangements that can be made with the letters of the word 'MATHEMATICS' in which all vowels come together, is
There are 4 vowels viz. A, E, A, I. Considering these four vowels as one letter we have 8 letters (M, T, H, M, T .. C, S and one letter obtained by combining all vowels), out or which M occurs twice, T occurs twice and the rest all different. These 8 letters can be arranged in ways.
But, the four vowels (A, E, A, I) can be put together in ways.
Hence, the total number of arrangements in which vowels are alwavs together .