GATE ECE 2011 | Question: 19

Question

The output $\mathrm{Y}$ in the circuit below is always $\text{“1"}$ when

• A. two or more of the inputs $\mathrm{P, Q, R}$ are $\text{“0"}$
• B. two or more of the inputs $\mathrm{P, Q, R}$ are $\text{“1"}$
• C. any odd number of the inputs $\mathrm{P, Q, R}$ is $\text{“0"}$
• D. any odd number of the inputs $\mathrm{P, Q, R}$ is $\text{“1"}$

Answer 1

solution

Answer 2

$Y = PQ + PR + QR$

$Y = 1$ iff at least two of the inputs $P,Q,R$ are $1.$