Question

How many 5-digit numbers divisible by 3 can be formed using digits 0, 2, 4, 6, 8, 9, if repetition not allowed?

Answer 1

Sum of digits = 0 + 2 + 4 + 6 + 8 + 9 = 29

So 5-digit numbers can be formed using the digits 0, 4, 6, 8, 9 or 0, 2, 4, 5, 9 as sum of digits is divisible by 3.

∴ total number of numbers formed is 2(4.4.!)=192