Answer:
[tex]36^6[/tex] postcodes
Step-by-step explanation:
Think of the post code as a combination lock
[?] [?] [?] [?] [?] [?]
If letters a numbers are allowed, each character can be A-Z and 0-9.
There are 26 letters, and 10 different digits
26 + 10 = 36 characters
Each block (I illustrated above) can be any of the 36 characters
If you have 2 blocks, you have a combination of
36 x 36 characters — which is the same as [tex]36^2[/tex]
With 3 blocks: [tex]36^3[/tex]
and so forth...
If your post code is made of 6 'blocks' it can be any combination of
[tex]36^6[/tex]
