IIT JEE , AIEEE Forum - Mathematics , Algebra

Anupamagrawal13a

The no of numbers divisible by 3 that can be formed by 4 different even digit is

Ans 36

Please solve this question with good explaination.

iitkgp_bipin

I assume they are 4-digit numbers.

Even digits are 0,2,4,6,8.

Find combinations of four numbers among these numbers such that their sum is a multiple of 3.

Two possibilities : (0,2,4,6) ; (0,4,6,8)

No. of numbers formed using (0,2,4,6) = 3x3x2x1 = 18 (since 0 cant be the 1st digit)

No. of numbers formed using (0,4,6,8) = 3x3x2x1 = 18 (since 0 cant be the 1st digit)

so total no. of such numbers = 18+18 = 36

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