MCA Entrance Previous Year Question Bank

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:

If all the six digit numbers $x_1{x}_2{x}_3{x}_4{x}_5{x}_6$ with 0 < x_1 < x_2 < x_3 < x_4 < x_5 < x_6 are arranged in the increasing order, then the sum of the digits in the $72^{\text{th}}$ number is

Five digit numbers are formed using the digits $1,2,3,5,7$ with repetitions and are written in descending order with serial numbers. For example, the number $77777$ has serial number $1$. Then the serial number of $35337$ is