How many 3-digit even number can be formed form the digits 1,2,3,4,5,6 if the digits can be repeated?

Explanation

First, for even number, 2 or 4 or 6 can be placed at unit place.
`:.` No. of ways of filling unti place = 3
No. of ways of filling ten's place = 6
No. of ways of filling huyndred's place = 6
Therefore, total even numbers `= 3 xx 6 xx 6 = 108`