The logical statement $[\sim(\sim \mathrm{p} \vee \mathrm{q}) \vee(\mathrm{p} \wedge \mathrm{r})]…

The logical statement $[\sim(\sim \mathrm{p} \vee \mathrm{q}) \vee(\mathrm{p} \wedge \mathrm{r})] \wedge(\sim \mathrm{q} \wedge \mathrm{r})$ is equivalent to
  1. $(p \wedge r) \wedge \sim q$
  2. $(p \wedge \sim q) \vee r$
  3. $\sim \mathrm{p} \vee \mathrm{r}$
  4. $\sim \mathrm{p} \wedge \mathrm{r}$

Solution

$\begin{aligned} & {[\sim(\sim p \vee q) \vee(p \wedge r)] \wedge(\sim q \wedge r)} \\ & \equiv[(p \wedge \sim q) \vee(p \wedge r)] \wedge(\sim q \wedge r) \\ & \text {...[De Morgan's law] } \\ & \equiv \mathrm{p} \wedge(\sim q \vee r) \wedge(\sim q \wedge r) \ldots \text {. [Distributive law] } \\ & \equiv \mathrm{p} \wedge[(\sim \mathrm{q} \vee \mathrm{r}) \wedge \sim \mathrm{q}] \wedge \mathrm{r} \ldots \text {... Associative law] } \\ & \equiv p \wedge(\sim q) \wedge r \quad \text {... [Absorption law] } \\ & \equiv(p \wedge r) \wedge \sim q \quad \ldots[\text { Commutative law }] \\ & \end{aligned}$

Asked in: MHT CET 2023 (10 May Shift 1)

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