1. a door code is made up of six unique digits the last digit is 8.

Question

2.oddd and even digits alternate(o is even)
3.the difference of the adjacent is always bigger than 1.
4.the first 2 digits (reads as one number)as well as he two middle digits(as one number) are multiples of the last two digits (as one number)

Answer 1

If the last digit is 8 the last two digits must be 18. A larger number ending in 8 would not have a two-digit multiple.

723618 could be the number. 367218 also works except for having the adjacent 6 and 7 differ by 1.