Vignesh: Y is one when $(A_2 \oplus B_2 \oplus A_1 \oplus B_1 \oplus A_0 \oplus B_0)$ is 0.
so when no of 1's is even.
That is $^6C_0+ ^6C_2 + ^6C_4 + ^6C_6 = 1+15+15+1= 32$
I think here are 30 combination
Got it mate so the answer is 16 right. Thanks a lot