Question

Let x be the number of integers lying between 2999 and 8001 which have at least two digits equal.Then X is equal to​

Answer 1

X can be 3333,3321,3141 etc.

Step-by-step explanation:

If x is that number then there are various numbers in between 2999 and 8001,which have atleast two digits equal

For example:3333,3321,3141,3112 etc.

Number of numbers in between 2999 and 8001=8001-2999-1

                                                                                   =5001

Numberof numbers starting with 3and all digit distinct =9×8× 7

                                                                                          =504

Similarly for number starting with 4,5,6,7=504 each

So total number of numbers =504×5

                                               =2520