What is the octal equivalent of (F3B1) hexadecimal number ?

First, convert each hexadecimal digit to its 4-bit binary equivalent: F=1111, 3=0011, B=1011, and 1=0001. This gives the binary string 1111001110110001. Next, group the binary digits into sets of three from right to left: 001 110 011 101 100 01. Finally, convert each octal group to its decimal value: 171661.