Maximum value that can be held by situations.

Please Help!!

What is the maximum value that can be held in the following situations? NOTE: give the maximum value in decimal and SHOW YOUR WORK (hexadecimal, duodecimal, tridecimal) (septenary, nonary, vigesimal) A byte, in a world where a bit allowed for four unique digits (instead of two) Two bytes, in a world where a bit allowed for six unique digits (instead of two)