1. If $$S\left( {p,q,r} \right) = \left( { \sim p} \right) \vee \left[ { \sim \left( {q \wedge r} \right)} \right]$$       is a compound statement, then $$S\left( { \sim p, \sim q, \sim r} \right)$$    is

A $$ \sim S\left( {p,q,r} \right)$$
B $$S\left( {p,q,r} \right)$$
C $$p \vee \left( {q \wedge r} \right)$$
D $$p \vee \left( {q \vee r} \right)$$
Answer :   $$p \vee \left( {q \vee r} \right)$$
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2. Let $$p$$ be the statement “$$x$$ is an irrational number”, $$q$$ be the statement “$$y$$ is a transcendental number”, and $$r$$ be the statement “$$x$$ is a rational number if $$f y$$  is a transcendental number”.
Statement - 1 : $$r$$ is equivalent to either $$q$$ or $$p$$
Statement - 2 : $$r$$ is equivalent to $$ \sim \left( {p \leftrightarrow \sim q} \right).$$

A Statement - 1 is false, Statement - 2 is true
B Statement - 1 is true, Statement - 2 is true ; Statement - 2 is a correct explanation for Statement - 1
C Statement - 1 is true, Statement - 2 is true ; Statement - 2 is not a correct explanation for Statement - 1
D none of these
Answer :   none of these
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3. Consider
Statement - 1 : $${\left( {{p^ \wedge } \sim q} \right)^ \wedge }\left( { \sim {p^ \wedge }q} \right)$$    is a fallacy.
Statement - 2 : $$\left( {p \to q} \right) \leftrightarrow \left( { \sim q \to \sim p} \right)$$     is a tautology.

A Statement - 1 is true; Statement - 2 is true; Statement - 2 is a correct explanation for Statement - 1.
B Statement - 1 is true; Statement - 2 is true; Statement - 2 is not a correct explanation for Statement - 1.
C Statement - 1 is true; Statement - 2 is false.
D Statement - 1 is false; Statement - 2 is true.
Answer :   Statement - 1 is true; Statement - 2 is true; Statement - 2 is not a correct explanation for Statement - 1.
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4. Which of the following is not logically equivalent to the proposition : “A real number is either rational or irrational.”

A If a number is neither rational nor irrational then it is not real
B If a number is not a rational or not an irrational, then it is not real
C If a number is not real, then it is neither rational nor irrational
D If a number is real, then it is rational or irrational
Answer :   If a number is not a rational or not an irrational, then it is not real
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5. The negation of $$ \sim s \vee \left( { \sim r \wedge s} \right)$$   is equivalent to:

A $$s \vee \left( {r \vee \sim s} \right)$$
B $${s \wedge r}$$
C $${s \wedge \sim r}$$
D $$s \wedge \left( {r \wedge \sim s} \right)$$
Answer :   $${s \wedge r}$$
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6. The contrapositive of $$\left( {p \vee q} \right) \Rightarrow r{\text{ is}}$$

A $$r \Rightarrow \left( {p \vee q} \right)$$
B $$ \sim r \Rightarrow \left( {p \vee q} \right)$$
C $$ \sim r \Rightarrow \sim p \wedge \sim q$$
D $$p \Rightarrow \left( {q \vee r} \right)$$
Answer :   $$ \sim r \Rightarrow \sim p \wedge \sim q$$
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7. Let $$p, q$$  and $$r$$ be any three logical statements. Which of the following is true ?

A $$ \sim \left[ {p \wedge \left( { \sim q} \right)} \right] \equiv \left( { \sim p} \right) \wedge q$$
B $$ \sim \left[ {\left( {p \vee q} \right) \wedge \left( { \sim r} \right)} \right. \equiv \left( { \sim p} \right) \vee \left( { \sim q} \right) \vee \left( { \sim r} \right)$$
C $$ \sim \left[ {p \vee \left( { \sim q} \right)} \right] \equiv \left( { \sim p} \right) \wedge q$$
D $$ \sim \left[ {p \vee \left( { \sim q} \right)} \right] \equiv \left( { \sim p} \right) \wedge {\sim q}$$
Answer :   $$ \sim \left[ {p \vee \left( { \sim q} \right)} \right] \equiv \left( { \sim p} \right) \wedge q$$
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8. Which of the following is a contradiction ?

A $$\left( {p \wedge q} \right) \wedge \sim \left( {p \vee q} \right)$$
B $$p \vee \left( { - p \wedge q} \right)$$
C $$\left( {p \Rightarrow q} \right) \Rightarrow p$$
D None of these
Answer :   $$\left( {p \wedge q} \right) \wedge \sim \left( {p \vee q} \right)$$
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9. Consider the two statements $$P :$$ He is intelligent and $$Q :$$ He is strong. Then the symbolic form of the statement ‘‘It is not true that he is either intelligent or strong’’ is

A $$ \sim P \vee Q$$
B $$ \sim P \wedge \sim Q$$
C $$ \sim P \wedge Q$$
D $$ \sim \left( {P \vee Q} \right)$$
Answer :   $$ \sim \left( {P \vee Q} \right)$$
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10. The negation of $$\left( {p \vee \sim q} \right) \wedge q{\text{ is}}$$

A $$\left( { \sim p \vee q} \right) \wedge \sim q$$
B $$\left( {p \wedge \sim q} \right) \vee q$$
C $$\left( { \sim p \wedge q} \right) \vee \sim q$$
D $$\left( {p \wedge \sim q} \right) \vee \sim q$$
Answer :   $$\left( { \sim p \wedge q} \right) \vee \sim q$$
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