WAEC Computer Studies 2020 Paper

Concept:The logic circuit shown in Figure 1 produces output $Z$ using a NAND gate. A NAND gate outputs $0$ only when both inputs are $1$; for all other input combinations, the output is $1$.Explanation:The given input values are $X = 1$ and $Y = 0$.First, compute the AND operation: $X \cdot Y = 1 \cdot 0 = 0$.A NAND gate gives the complement of the AND result: $Z = \overline{X \cdot Y}$.So, $Z = \overline{0} = 1$.Hence, when $X = 1$ and $Y = 0$, the output $Z$ becomes $1$.Answer:$Z = 1$, that is, option B.