The letters of the word OUGHT are written in all possible ways and these words are arranged as in a dictionary, in a series. Then the serial number of the word TOUGH is :

Step-by-step solution

Lets arrange the letters of OUGHT in alphabetical order. G , H , O , T , U Number of words starting with G = 4 ! = 24 Number of words starting with H = 4 ! = 24 Number of words starting with O = 4 ! = 24 Number of words starting with T G 3 ! = 6 ! Number of words starting with T H = 3 ! = 6 Number of words starting with T O G = 2 ! = 2 Number of words starting with T O H = 2 ! = 2 Next word is TOUGH . Hence, the serial number of the word TOUGH is = 24 + 24 + 24 + 6 + 6 + 2 + 2 + 1 = 89