Letters in word COMPUTER are C, O, M, P, U, T, E, R.
∴ Ascending order of letter in word COMPUTER according to dictionary order is C, E, M, O, P, R, T, U.
C is fixed for smallest order in dictionary.
Number of words starting with CE = 6! = 720,
Number of words starting with CM = 6! = 720,
Number of words starting with COE = 5! = 120,
Number of words starting with COME = 4! = 24,
Number of words starting with COMPE = 3! = 6,
Number of words starting with COMPR = 3! = 6,
Number of words starting with COMPT = 3! = 6,
Number of words starting with COMPUE = 2! = 2,
Number of words starting with COMPUR = 2! = 2,
After these words, COMPUTER is next word.
∴ Rank of word COMPUTER = 720 + 720 + 120 + 24 + 6 + 6 + 6 + 2 + 2 + 1 = 1607.