Answer:
1F5
Explanation:
First convert octal 765 into binary values with each octal digit as a representation using 3 bits
Octal 7 ==> 111
Octal 6 ==> 110
Octal 5 ==> 101
Putting it together we get
111110101
Now group the bit values into groups of 4 (with leading zeros if necessary) starting with the rightmost bit.
Groups are highlighted and then the hex value is written
Right-most group 111110101 and 0101 is 5 hex
Middle group: 111110101 and 1111 is F hex
Left most group: 111110101 ; with leading zeros it is 0001 which is 1 hex
So from left to right we get 1F5
