In how many ways a 5 digit numbers divisible by 6 can be formed by the digits 0, 1, 2, 4, 5, 6 without repetition
Answers
Answer:
108 is correct answer
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HELLO DEAR,
GIVEN:- A five digit number divisible by 6 is to be formed by using 0,1,2,3,4,5 without repetition.
To find the number of ways in which this can be done.
SOLUTION:-
We have to select such a way the arrangement of digits to make it divisible by 6.
And 6 is divisible by 2 and 3.
Therefore ,the number which is divisible by 6 is also divisible by 2 and 3.
we need to use the divisibility rules for both 2 and 3 .
The last digit is even is divisible by 2.
The sum of the digits is divisible by 3 then that number is divisible by 3.
First select the five digits whose sum is divisible by 3:
Sum of all givin digits = 15 which is a multiple of 3.
Case1:
1,2,3,4,5 are chosen.
For the number to be divisible by 2 last digit is 2 or 4.
Thus ,the number of ways = 4! ×2!
= 48.
Case2:-
0,1,2,4,5 are chosen.
a) if last two digit 0, number of ways = 4! = 24.
b) lyf last digit is to the other digits may be filled in from left to right
3×3×2×1= 18 ways
c) if last digit is 4 ,the other digits may be filled in from left to right,
3×3×2×1 = 18 ways
So, the answer = 48+24+18+18=108 ways.