The 1’s complement of a number is obtained by reversing the bits with value 1 to 0 and the bits with value 0 to 1.
Here, 0.101 gets converted to 1.010 in its 1’s complement format.

To convert octal to hexadecimal, we first write binary format of the number and then make groups of 4 bits from right to left, as follows:
 5     4      0     1
101   100    000    001   (octal -> binary)
1011     0000    0001     ( groups of 4)
B         0       1       ( hexadecimal equivalent)
Therefore, the hexadecimal equivalent is (B01)16.

 The first bit is the sign bit whereas the rest of the bits are magnitude bits. So the number is: 0010 = 21 * 1 =2
But, the sign bit is 1, Therefore the answer is : (-2)10.

 The symbols A, B, C, D, E and F represent 10, 11, 12, 13, 14 and 15 respectively in a hexadecimal system. This system comprises of 15 numbers in total: digits from 0-9 and symbols from A to F.

The hexadecimal number system comprises of only 15 symbols: 10 digits and 5 symbols. Hence, three bits (24 = 16 ) are sufficient to represent any hexadecimal number in the binary format.