(FE35)BASE 16 = 1111 1110 0011 0101
(CB15)BASE 16 = 1100 1011 0001 0101
as we know that for XOR operation for the same input give o and for different input give 1
so using this we get: 0011 0101 0010 0000
converting it into HEXA Decimal we get (3520) BASE 16.