Section A — MCQ (Single Correct)
Question 1
The statement $(\sim(p \Leftrightarrow q)) \Leftrightarrow ((p \wedge \sim q) \vee (\sim p \wedge q))$ is:
A
A tautology
B
A contradiction
C
Neither tautology nor contradiction
D
Equivalent to $p \wedge q$
Question 2
The Boolean expression $\sim(p \vee q) \vee (\sim p \wedge q)$ is equivalent to:
A
$\sim p$
B
$p$
C
$q$
D
$\sim q$
Question 3
Let $p$: "A quadrilateral is a square", $q$: "Its diagonals are equal", $r$: "Its diagonals are perpendicular". The statement $p \Rightarrow (q \wedge r)$ is:
A
True with $\sim p$ being a converse of $\sim q \vee \sim r$
B
Equivalent to $\sim(q \wedge r) \Rightarrow \sim p$
C
Equivalent to $(\sim q \vee \sim r) \Rightarrow \sim p$
D
Both (B) and (C)
Question 4
The statement $(p \Rightarrow q) \Leftrightarrow (\sim q \Rightarrow \sim p)$ is:
A
A tautology
B
A contradiction
C
Contingent on $p$
D
Contingent on $q$
Question 5
The negation of the compound statement "$\sqrt{2}$ is irrational and 2 is prime" is:
A
$\sqrt{2}$ is rational and 2 is not prime
B
$\sqrt{2}$ is rational or 2 is not prime
C
$\sqrt{2}$ is irrational or 2 is not prime
D
$\sqrt{2}$ is rational and 2 is prime
Question 6
Consider the argument: "If a number is divisible by 6, then it is divisible by both 2 and 3. The number $n$ is divisible by 2 and 3. Therefore $n$ is divisible by 6." This argument is:
A
Valid by Modus Ponens
B
Invalid due to affirming the consequent
C
Valid by Modus Tollens
D
Sound (valid and premises are true)
Question 7
Which of the following is a valid argument form?
A
$p \Rightarrow q$, $r \Rightarrow s$, $p \vee r$, therefore $q \vee s$
B
$p \Rightarrow q$, $\sim p$, therefore $\sim q$
C
$p \Rightarrow q$, $q$, therefore $p$
D
$p \Leftrightarrow q$, $\sim p$, therefore $q$
Question 8
The Boolean expression $((p \cdot q')' \cdot (p' + q))'$ simplifies to:
A
$p \cdot q'$
B
$p' + q$
C
$p \cdot q$
D
$p + q'$
Question 9
If $p$ is the statement "Ravi is hardworking" and $q$ is "Ravi will get a job", then the statement "Ravi will get a job if and only if he is hardworking" is:
A
$p \Rightarrow q$
B
$q \Rightarrow p$
C
$p \Leftrightarrow q$
D
$\sim p \vee q$
Question 10
The contrapositive of "$(p \Rightarrow q) \Rightarrow r$" is:
A
$\sim r \Rightarrow \sim(p \Rightarrow q)$, i.e., $\sim r \Rightarrow (p \wedge \sim q)$
B
$\sim r \Rightarrow (\sim p \Rightarrow \sim q)$
C
$r \Rightarrow (p \Rightarrow q)$
D
$\sim(p \Rightarrow q) \Rightarrow \sim r$
Section B — Integer Type
Question 11 — Integer answer
Consider 4 atomic statements $p, q, r, s$. How many rows are there in the corresponding truth table?
Question 12 — Integer answer
The number of distinct truth tables (functions from $\{T, F\}^2 \to \{T, F\}$) that can be defined for two atomic statements $p, q$ is $2^k$. Find $k$.
Question 13 — Integer answer
How many of the following are tautologies?
(i) $p \vee \sim p$, (ii) $p \wedge \sim p$, (iii) $(p \Rightarrow q) \vee (q \Rightarrow p)$, (iv) $(p \Rightarrow q) \Leftrightarrow (\sim p \vee q)$
Section C — Assertion & Reasoning
Question 14 — Assertion / Reason
Assertion (A): The statement "If $n$ is an integer and $n^2$ is even, then $n$ is even" can be efficiently proven by contrapositive.
Reason (R): The contrapositive "If $n$ is odd, then $n^2$ is odd" is straightforward to prove directly using $n = 2k+1$.
A
Both A and R are true and R is the correct explanation of A
B
Both A and R are true but R is NOT the correct explanation of A
C
A is true but R is false
D
A is false but R is true
Solution: Both A and R are true, and R correctly explains A.
Question 15 — Assertion / Reason
Assertion (A): For any propositions $p$ and $q$, the proposition $p \Rightarrow q$ is logically equivalent to $\sim p \vee q$.
Reason (R): Truth table analysis confirms that $p \Rightarrow q$ and $\sim p \vee q$ have identical truth values for all combinations of $p$ and $q$.
A
Both A and R are true and R is the correct explanation of A
B
Both A and R are true but R is NOT the correct explanation of A
C
A is true but R is false
D
A is false but R is true
Solution: Both A and R are true, and R correctly explains A.