A letter look consists of three rings marked with 15 different letters. If N denotes the number of ways in which it is possibel to make unsuccessful attempts to open lock, then

A letter lock consists of three rings marked with 15 different letters . If N denotes the number of ways in which it is possible to make unsuccessful attempts to open the lock, then

A letter lock consists of 4 rings each marked with 10 different letters, the number of ways in which it is possible to make an unsuccessful attempts to open the lock is

A letter lock consists of three rings each marked with 10 different letters. In how many ways it is possible to make an unsuccessful attempt to open the lock?

A letter lock consists of three rings each marked with 10 different letters.In how many ways it is possible to make an unsuccessful attempt to open the lock?

A letter lock consists of three rings each marked with 5 different letters. Number of maximum attempts to open the lock is

a Letter lock contains 5 rings each marked with four different letters . The number of all possible iunsuccesful attempts to open the lock is

A letter lock consists of three rings each marked with 10 different letters. No. of ways to make an unsuccessful attempts to open the lock is

Let N denotes the number of ways in which 3n letters can be selected from 2n A's, 2nB's and 2nC's. then,

Let N denotes the number of ways in which 3n letters can be selected from 2n A's, 2nB's and 2nC's. then,

Seven different letters are given. Then the number of ways in which , words of 5 letters can be formed such that atleast one of the letters is repeated is