Question

How many 3-digit numbers exist, whose digits are distinct even numbers.

Answer 1

100

Explanation:

my teacher told me and I got it right

Answer 2

328

Explanation:

If z is 0, then x has 9 choices. Therefore, z and x can be chosen in (1 × 9) + (4 × 8) = 41 ways. For each of these ways, y can be chosen in 8 ways. Hence, the desired number is 41 × 8 = 328 numbers 3-digit even numbers exist with no repetitions.