Verified Solution • 2025–26 Session moderate

QJEEM23Mabc4b: JEE Main 2023 Mathematics - Class 11 JEEM23Mabc4b Solution: The total number of six digit numbers, formed using the digits…

The total number of six digit numbers, formed using the digits 4, 5, 9 only and divisible by 6, is ____________.

Step-by-Step Verified Solution

A number will be divisible by 6 iff the digit at the unit place of the number is divisible by 2 and sum of all digits of the number is divisible by 3 .

Units, place must be occupied by 4 and hence, at least one 4 must be there.

Possible combination of 4, 5, 9 are as follows :

4 5 9 Total number
of Number
1 1 4 5!4!=5{{5!} \over {4!}} = 5
1 4 1 5!4!=5{{5!} \over {4!}} = 5
2 2 2 5!2!2!=30{{5!} \over {2!2!}} = 30
3 0 3 5!2!3!=10{{5!} \over {2!3!}} = 10
3 3 0 5!2!3!=10{{5!} \over {2!3!}} = 10
4 1 1 5!3!=20{{5!} \over {3!}} = 20
6 0 0 5!5!=1{{5!} \over {5!}} = 1


Total = 5 + 5 + 30 + 10 + 10 + 20 + 1 = 81.

Related Learning Resources & Exam Preparation