Section A — MCQ (Single Correct)
Question 1
The negation of "If $n$ is a prime number, then $n$ is odd or $n = 2$" is:
A
$n$ is a prime number and $n$ is even and $n \neq 2$
B
$n$ is not a prime number or $n$ is odd or $n = 2$
C
$n$ is a prime number and ($n$ is even or $n = 2$)
D
$n$ is not prime and $n$ is even and $n \neq 2$
Question 2
Which of the following is the contrapositive of "If two triangles are congruent, then their areas are equal"?
A
If two triangles are not congruent, then their areas are not equal
B
If the areas of two triangles are equal, then they are congruent
C
If the areas of two triangles are not equal, then they are not congruent
D
If two triangles are congruent, then their areas are not equal
Question 3
The compound statement $(p \wedge q) \Rightarrow (p \vee q)$ is:
A
A tautology
B
A contradiction
C
A contingency
D
Neither tautology nor contradiction
Question 4
The negation of "$\forall x \in \mathbb{R}, \exists y \in \mathbb{R}, y > x$" is:
A
$\exists x \in \mathbb{R}, \forall y \in \mathbb{R}, y \leq x$
B
$\forall x \in \mathbb{R}, \forall y \in \mathbb{R}, y \leq x$
C
$\exists x \in \mathbb{R}, \exists y \in \mathbb{R}, y \leq x$
D
$\exists x \in \mathbb{R}, \forall y \in \mathbb{R}, y > x$
Question 5
Let $p$: "Suman is brilliant" and $q$: "Suman is rich". The compound statement "Suman is neither brilliant nor rich" is:
A
$\sim p \wedge \sim q$
B
$\sim(p \vee q)$
C
$\sim(p \wedge q)$
D
Both (A) and (B)
Question 6
If $p \Rightarrow (q \vee r)$ is false, then the truth values of $p, q, r$ are respectively:
A
$T, F, F$
B
$F, F, F$
C
$F, T, T$
D
$T, T, F$
Question 7
The converse of "If $x$ is an even integer, then $x + 2$ is an even integer" is:
A
If $x + 2$ is not even, then $x$ is not even
B
If $x$ is not even, then $x + 2$ is not even
C
If $x + 2$ is an even integer, then $x$ is an even integer
D
If $x + 2$ is an odd integer, then $x$ is an odd integer
Question 8
Which of the following is a tautology?
A
$(p \Rightarrow q) \Leftrightarrow (\sim q \Rightarrow \sim p)$
B
$p \wedge \sim p$
C
$(\sim p) \Rightarrow p$
D
$p \Rightarrow (p \wedge q)$
Question 9
The statement $\sim(p \Leftrightarrow \sim q)$ is logically equivalent to:
A
$p \Leftrightarrow q$
B
$\sim p \Leftrightarrow \sim q$
C
$p \Leftrightarrow \sim q$
D
Both (A) and (B)
Question 10
The negation of the statement "If $x$ is real, then $x^2 \geq 0$" is:
A
There exists a real number $x$ such that $x^2 < 0$
B
For every real number $x$, $x^2 < 0$
C
There exists a real number $x$ such that $x^2 \geq 0$
D
$x$ is not real or $x^2 < 0$
Section B — Integer Type
Question 11 — Integer answer
How many distinct truth value combinations are there in the truth table of a compound statement involving exactly 3 atomic statements $p, q, r$? (Give the integer value.)
Question 12 — Integer answer
Consider the compound statement $(p \Rightarrow q) \wedge (q \Rightarrow r) \Rightarrow (p \Rightarrow r)$. The number of rows in the truth table where this compound statement is TRUE is (out of 8 rows total).
Question 13 — Integer answer
For how many truth value assignments to $(p, q)$ is the statement $p \Leftrightarrow q$ true (out of the 4 possible assignments)?
Section C — Assertion & Reasoning
Question 14 — Assertion / Reason
Assertion (A): The contrapositive of "If $x$ is a multiple of 6, then $x$ is a multiple of 2" is logically equivalent to the original statement.
Reason (R): For any conditional statement $p \Rightarrow q$, the contrapositive $\sim q \Rightarrow \sim p$ is logically equivalent to it.
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): The statement $p \vee \sim p$ is always true regardless of the truth value of $p$.
Reason (R): This is known as the Law of Excluded Middle, a fundamental tautology in classical logic.
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.