The number of all 4-digit number of the form `5n+2 (n in n)` having exactly one digit 7

n-digit number

A number is selected from 4 digit numbers of the form 5n+2 where n belongs to N containing exactly one digit as 7 . Find the probability that number when divided by 5 leaves remainder 2.

The number of 4 digit numbers that can be made using exactly two digits out of 1,2,3,4,5,6 and 7

The number of n digit numbers which consists of the digit 1 and 2 only if each digit is to be used at least nece is equal to 510, then n is equal to

If N is the number of three digit numbers of the form abc such that a

The number of all 2-digit numbers n such that n is equal the sum of the square of digit in its tens place and the cube of the digit in units place is

The number of n-digit numbers which contain the digits 2 and 7, but not the digits 0,1,8,9, is

Find the total number of n -digit number (n>1) having property that no two consecutive digits are same.

Any number of the form 4^(n), n != N can never end with the digit