Answer:

4095

Hopefully you did something clever: you realized that the represented number is 2^N - 1 which must be an odd number. ( 2^N means 2 × 2 × 2 ... × 2 it must be even. So 2^N - 1 must be odd. )

So you picked the only odd number in the list. Or else you ignored the question.

Base 16 Representation

Recall the Rules for Positional Notation:

The base B is (usually) a positive integer.
There are B "digits" representing zero up to (B minus one).
Positions correspond to integer powers of B, starting with power zero, and increasing right to left.
The digit placed at a position shows how many times that power of B is included in the number.

Rule 1 says any positive integer can be used as a base. Let's use sixteen as a base. Rule 2 says we need sixteen symbols to use as digits. Here is the usual choice:

zero	one	two	three	four	five	six	seven
0	1	2	3	4	5	6	7
eight	nine	ten	eleven	twelve	thirteen	fourteen	fifteen
8	9	A	B	C	D	E	F

Since there are only ten of the usual digits, letters are used for the remaining six hex "digits".

Base sixteen representation is called the Hexadecimal system, sometimes called Hex.

QUESTION 7:

Fill in the blanks with BASE SIXTEEN digits

31A (base sixteen)   =     × sixteen² +  × sixteen¹ +   × sixteen⁰