Question

Sol. [Key Concept: Identifying the equivalent logic gate output]

$$\begin{matrix} Y_{1} & \ = \overline{A \cdot A} \\ & \ = \bar{A} \\ Y_{2} & \ = \overline{B + B} \\ & \ = \bar{B} \end{matrix}$$

$$\begin{matrix} Y = & \overline{Y_{1} + Y_{2}} \\ = & \overline{\bar{A} + \bar{B}} \\ = & \overline{\bar{A}} \cdot \overline{\bar{B}} \\ & \ = A \cdot B\text{~}\text{is similar to output of AND Gate}\text{~} \end{matrix}$$