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2,749 questions · 40 years · 20 subjects

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80 questions shown in Discrete Mathematics. Filter for cleaner practice sessions.

Showing Discrete Mathematics PYQs from CSE & IT.
2026 PYQ

Consider $4 \times 4$ matrices with their elements from $\{0,1\}$. The number of such matrices with even number of 1 s in every row and every column is

Discrete Mathematics/MCQ/answer key/explanation
2026 PYQ

For $n>1$, the maximum multiplicity of any eigenvalue of an $n \times n$ matrix with elements from $\mathbb{R}$ is

Discrete Mathematics/MCQ/answer key/explanation
2026 PYQ

Let $n>1$. Consider an $n \times n$ matrix $M$ with its elements from $\mathbb{R}$. Let the vector ( 0,1 , $0,0, \ldots, 0) \in \mathbb{R}^n$ be in the null space of $M$. Which of...

Discrete Mathematics/MSQ/answer key/explanation
2026 PYQ

Consider the function $f: \mathbb{R} \rightarrow \mathbb{R}$ defined as follows: $$ f(x)=\left\{\begin{array}{cc} c_1 e^x-c_2 \log _e\left(\frac{1}{x}\right), & \text { if } x>0 \\...

Discrete Mathematics/NAT/explanation
2026 PYQ

Let $G(V, E)$ be a simple, undirected graph. A vertex cover of $G$ is a subset $V^{\prime} \subseteq V$ such that for every $(u, v) \in E, u \in V^{\prime \prime}$ or $v \in V^{\pr...

Discrete Mathematics/MCQ/answer key/explanation
2026 PYQ

Let $G$ be an undirected graph, which is a path on 8 vertices. The number of matchings in $G$ is $\_\_\_\_$ (answer in integer)

Discrete Mathematics/NAT/explanation
2026 PYQ

Let $X$ be a random variable which takes values in the set $\{1,2,3,4,5,6,7,8\}$. Further, $\operatorname{Pr}(X=1)=\operatorname{Pr}(X=2)=\operatorname{Pr}(X=5)=\operatorname{Pr}(X...

Discrete Mathematics/NAT/explanation
2026 PYQ

For two different persons $x$ and $y$, the predicate $M(x, y)$ denotes that $x$ knows $y$. Consider the following statement. There is a person who does not know anyone else, but th...

Discrete Mathematics/MCQ/answer key/explanation
2026 PYQ

The probability density function $f(x)$ of a random variable $X$ which takes real values is $$ f(x)=\frac{1}{3 \sqrt{2 \pi}} \exp \left(-\frac{x^2}{18}\right), x \in(-\infty,+\inft...

Discrete Mathematics/MCQ/answer key/explanation
2026 PYQ

Let $R$ be a binary relation on the set $\{1,2, \ldots, 10\}$, where $(x, y) \in, R$ if the product of $x$ and $y$ is square of an integer. Which of the following properties is/are...

Discrete Mathematics/MSQ/answer key/explanation
2026 PYQ

For a real number $a$, let $I(a)=\int\limits_{-1}^1\left(3 x^2-a x+1\right) d x$. Which of the following statements is/are true?

Discrete Mathematics/MSQ/answer key/explanation
2026 PYQ

Consider the system of linear equations given below. $$ \begin{aligned} a x+y & =b \\ 16 x+a y & =24 \end{aligned} $$ Suppose the values of a and b are chosen such that the system...

Discrete Mathematics/NAT/explanation
2026 PYQ

Consider a complete graph $K_n$ with $n$ vertices ( $n>4$ ). Note that multiple spanning trees can be constructed over $K_n$. Each of these spanning trees is represented as a set o...

Discrete Mathematics/MCQ/answer key/explanation
2026 PYQ

Suppose an unbiased coin is tossed 6 times. Each coin toss is independent of all previous coin tosses. Let $E_1$ be the event that among the second, fourth, and sixth coin tosses,...

Discrete Mathematics/NAT/explanation
2026 PYQ

Consider a function $f:(0,1) \rightarrow\{0,1\}$ defined as follows. For a real number $r \in(0,1), f(r)=1$ if the second digit after the decimal point in $r$ is one of the four di...

Discrete Mathematics/INTEGER/explanation
2026 PYQ

Let $f: \mathbb{R} \rightarrow \mathbb{R}$ be defined as follows: $$ f(x)=\left(\frac{|x|}{2}-x\right)\left(x-\frac{|x|}{2}\right) $$ Which of the following statements is/are true?

Discrete Mathematics/MSQ/answer key/explanation
2026 PYQ

An urn contains one red ball and one blue ball. At each step, a ball is picked uniformly at random from the urn, and this ball together with another ball of the same color is put b...

Discrete Mathematics/MCQ/answer key/explanation
2025 PYQ

Which of the following predicate logic formulae/formula is/are CORRECT representation(s) of the statement: "Everyone has exactly one mother"? The meanings of the predicates used ar...

Discrete Mathematics/MSQ/answer key/explanation
2025 PYQ

Let $S$ be the set of all ternary strings defined over the alphabet $\{a, b, c\}$. Consider all strings in $S$ that contain at least one occurrence of two consecutive symbols, that...

Discrete Mathematics/NAT/explanation
2025 PYQ

Let $A$ be a $2 \times 2$ matrix as given. $$A=\left[\begin{array}{cc} 1 & 1 \\ 1 & -1 \end{array}\right]$$ What are the eigenvalues of the matrix $A^{13}$ ?

Discrete Mathematics/MCQ/answer key/explanation
2025 PYQ

Consider the given system of linear equations for variables $x$ and $y$, where $k$ is a realvalued constant. Which of the following option(s) is/are CORRECT? $$\begin{aligned} & x+...

Discrete Mathematics/MSQ/answer key/explanation
2025 PYQ

$A=\{0,1,2,3, \ldots\}$ is the set of non-negative integers. Let $F$ be the set of functions from $A$ to itself. For any two functions, $f_1, f_2 \in \mathrm{~F}$ we define $$\left...

Discrete Mathematics/MSQ/answer key/explanation
2025 PYQ

Suppose a 5-bit message is transmitted from a source to a destination through a noisy channel. The probability that a bit of the message gets flipped during transmission is 0.01. F...

Discrete Mathematics/NAT/explanation
2025 PYQ

Consider a probability distribution given by the density function $P(x)$. $$P(x)=\left\{\begin{array}{cc} C x^2, & \text { for } 1 \leq x \leq 4 \\ 0, & \text { for } x 4 \end{arra...

Discrete Mathematics/NAT/explanation
2025 PYQ

Consider the given function $f(x)$. $$f(x)=\left\{\begin{array}{cc} a x+b & \text { for } x If the function is differentiable everywhere, the value of $b$ must be _________ (Rounde...

Discrete Mathematics/NAT/explanation
2025 PYQ

$g(.)$ is a function from A to B, $f(.)$ is a function from B to C, and their composition defined as $f(g(.))$ is a mapping from A to C. If $f(.)$ and $f(g(.))$ are onto (surjectiv...

Discrete Mathematics/MCQ/answer key/explanation
2025 PYQ

A box contains 5 coins: 4 regular coins and 1 fake coin. When a regular coin is tossed, the probability $P($ head $)=0.5$ and for a fake coin, $P($ head $)=1$. You pick a coin at r...

Discrete Mathematics/NAT/explanation
2025 PYQ

The value of $x$ such that $x>1$, satisfying the equation $\int_1^x t \ln t d t=\frac{1}{4}$ is

Discrete Mathematics/MCQ/answer key/explanation
2025 PYQ

Consider a system of linear equations $P X=Q$ where $P \in \mathbb{R}^{3 \times 3}$ and $Q \in \mathbb{R}^{3 \times 3}$. Suppose $P$ has an $L U$ decomposition, $P=L U$, where $$L=...

Discrete Mathematics/MSQ/answer key/explanation
2025 PYQ

A quadratic polynomial $(x-\alpha)(x-\beta)$ over complex numbers is said to be square invariant if $(x-\alpha)(x-\beta)=\left(x-\alpha^2\right)\left(x-\beta^2\right)$. Suppose fro...

Discrete Mathematics/NAT/explanation
2025 PYQ

If $A=\left(\begin{array}{cc}1 & 2 \\ 2 & -1\end{array}\right)$, then which ONE of the following is $A^8$ ?

Discrete Mathematics/MCQ/answer key/explanation
2025 PYQ

Let $L, M$, and $N$ be non-singular matrices of order 3 satisfying the equations $L^2=L^{-1}, M=L^8$ and $N=L^2$. Which ONE of the following is the value of the determinant of $(M-...

Discrete Mathematics/MCQ/answer key/explanation
2025 PYQ

Let $P(x)$ be an arbitrary predicate over the domain of natural numbers. Which ONE of the following statements is TRUE?

Discrete Mathematics/MCQ/answer key/explanation
2025 PYQ

The unit interval $(0,1)$ is divided at a point chosen uniformly distributed over $(0,1)$ in $R$ into two disjoint subintervals. The expected length of the subinterval that contain...

Discrete Mathematics/NAT/explanation
2025 PYQ

Let $F$ be the set of all functions from $\{1, \ldots, n\}$ to $\{0,1\}$. Define the binary relation $\preccurlyeq$ on $F$ as follows: $\forall f . g \in F, f \preccurlyeq g$ if an...

Discrete Mathematics/MSQ/answer key/explanation
2024 PYQ

Let $f : \mathbb{R} \rightarrow \mathbb{R}$ be a function such that $f(x) = \max \{x, x^3\}, x \in \mathbb{R}$, where $\mathbb{R}$ is the set of all real numbers. The set of all po...

Discrete Mathematics/MCQ/answer key/explanation
2024 PYQ

The product of all eigenvalues of the matrix $\begin{bmatrix} 1 & 2 & 3 \\ 4 & 5 & 6 \\ 7 & 8 & 9 \end{bmatrix}$ is

Discrete Mathematics/MCQ/answer key/explanation
2024 PYQ

Consider a permutation sampled uniformly at random from the set of all permutations of {1, 2, 3, ..., n } for some n ≥ 4. Let X be the event that 1 occurs before 2 in the permutati...

Discrete Mathematics/MCQ/answer key/explanation
2024 PYQ

Let A and B be two events in a probability space with $P(A) = 0.3$, $P(B) = 0.5$, and $P(A \cap B) = 0.1$. Which of the following statements is/are TRUE?

Discrete Mathematics/MSQ/answer key/explanation
2024 PYQ

Let $A$ and $B$ be non-empty finite sets such that there exist one-to-one and onto functions (i) from $A$ to $B$ and (ii) from $A \times A$ to $A \cup B$. The number of possible va...

Discrete Mathematics/NAT/explanation
2024 PYQ

The number of spanning trees in a complete graph of 4 vertices labelled A, B, C, and D is __________

Discrete Mathematics/NAT/explanation
2024 PYQ

Let A be any n x m matrix, where m > n . Which of the following statements is/are TRUE about the system of linear equations Ax = 0 ?

Discrete Mathematics/MSQ/answer key/explanation
2024 PYQ

The chromatic number of a graph is the minimum number of colours used in a proper colouring of the graph. Let $G$ be any graph with $n$ vertices and chromatic number $k$. Which of...

Discrete Mathematics/MSQ/answer key/explanation
2024 PYQ

Consider the operators $\diamond$ and $\square$ defined by $a \diamond b=a+2 b, a \square b=a b$, for positive integers. Which of the following statements is/are TRUE?

Discrete Mathematics/MSQ/answer key/explanation
2024 PYQ

The number of edges present in the forest generated by the DFS traversal of an undirected graph G with 100 vertices is 40. The number of connected components in G is ________

Discrete Mathematics/NAT/explanation
2024 PYQ

A bag contains 10 red balls and 15 blue balls. Two balls are drawn randomly without replacement. Given that the first ball drawn is red, the probability (rounded off to 3 decimal p...

Discrete Mathematics/NAT/explanation
2024 PYQ

Let p and q be the following propositions: p : Fail grade can be given. q : Student scores more than 50% marks. Consider the statement: “Fail grade cannot be given when student sco...

Discrete Mathematics/MCQ/answer key/explanation
2024 PYQ

Let $f(x)$ be a continuous function from $\mathbb{R}$ to $\mathbb{R}$ such that $f(x) = 1 - f(2 - x)$ Which one of the following options is the CORRECT value of $\int_0^2 f(x) dx$?

Discrete Mathematics/MCQ/answer key/explanation
2024 PYQ

Let $A$ be the adjacency matrix of a simple undirected graph $G$. Suppose $A$ is its own inverse. Which one of the following statements is always TRUE?

Discrete Mathematics/MCQ/answer key/explanation
2024 PYQ

When six unbiased dice are rolled simultaneously, the probability of getting all distinct numbers (i.e., 1, 2, 3, 4, 5, and 6) is

Discrete Mathematics/MCQ/answer key/explanation
2024 PYQ

Let $P$ be the partial order defined on the set {1,2,3,4} as follows: $P = \{(x, x) \mid x \in \{1,2,3,4\}\} \cup \{(1,2), (3,2), (3,4)\}$ The number of total orders on {1,2,3,4} t...

Discrete Mathematics/NAT/explanation
2024 PYQ

Let $ x $ and $ y $ be random variables, not necessarily independent, that take real values in the interval $[0,1]$. Let $ z = xy $ and let the mean values of $ x, y, z $ be $ \bar...

Discrete Mathematics/MCQ/answer key/explanation
2024 PYQ

Let A be an n × n matrix over the set of all real numbers ℝ. Let B be a matrix obtained from A by swapping two rows. Which of the following statements is/are TRUE?

Discrete Mathematics/MSQ/answer key/explanation
2024 PYQ

Let Z n be the group of integers {0, 1, 2, ..., n − 1} with addition modulo n as the group operation. The number of elements in the group Z 2 × Z 3 × Z 4 that are their own inverse...

Discrete Mathematics/NAT/explanation
2023 PYQ

The Lucas sequence $$L_n$$ is defined by the recurrence relation: $${L_n} = {L_{n - 1}} + {L_{n - 2}}$$, for $$n \ge 3$$, with $${L_1} = 1$$ and $${L_2} = 3$$. Which one of the opt...

Discrete Mathematics/MCQ/answer key/explanation
2023 PYQ

Let $$A = \left[ {\matrix{ 1 & 2 & 3 & 4 \cr 4 & 1 & 2 & 3 \cr 3 & 4 & 1 & 2 \cr 2 & 3 & 4 & 1 \cr } } \right]$$ and $$B = \left[ {\matrix{ 3 & 4 & 1 & 2 \cr 4 & 1 & 2 & 3 \cr 1 &...

Discrete Mathematics/MCQ/answer key/explanation
2023 PYQ

Geetha has a conjecture about integers, which is of the form $$\forall x\left( {P(x) \Rightarrow \exists yQ(x,y)} \right)$$, where P is a statement about integers, and Q is a state...

Discrete Mathematics/MSQ/answer key/explanation
2023 PYQ

Let $$f(x) = {x^3} + 15{x^2} - 33x - 36$$ be a real-valued function. Which of the following statements is/are TRUE?

Discrete Mathematics/MSQ/answer key/explanation
2023 PYQ

The value of the definite integral $$\int\limits_{ - 3}^3 {\int\limits_{ - 2}^2 {\int\limits_{ - 1}^1 {(4{x^2}y - {z^3})dz\,dy\,dx} } } $$ is ___________. (Rounded off to the neare...

Discrete Mathematics/NAT/explanation
2023 PYQ

Let $$U = \{ 1,2,....,n\} $$, where n is a large positive integer greater than 1000. Let k be a positive integer less than n. Let A, B be subsets of U with $$|A| = |B| = k$$ and $$...

Discrete Mathematics/MCQ/answer key/explanation
2023 PYQ

Let $$f:A \to B$$ be an onto (or surjective) function, where A and B are nonempty sets. Define an equivalence relation $$\sim$$ on the set A as $${a_1} \sim {a_2}$$ if $$f({a_1}) =...

Discrete Mathematics/MSQ/answer key/explanation
2023 PYQ

Let X be a set and 2$$^X$$ denote the powerset of X. Define a binary operation $$\Delta$$ on 2$$^X$$ as follows: $$A\Delta B=(A-B)\cup(B-A)$$. Let $$H=(2^X,\Delta)$$. Which of the...

Discrete Mathematics/MSQ/answer key/explanation
2023 PYQ

Consider a random experiment where two fair coins are tossed. Let A be the event that denotes HEAD on both the throws, B be the event that denotes HEAD on the first throw, and C be...

Discrete Mathematics/MSQ/answer key/explanation
2023 PYQ

Let G be a simple, finite, undirected graph with vertex set {$$v_1,...,v_n$$}. Let $$\Delta(G)$$ denote the maximum degree of G and let N = {1, 2, ...} denote the set of all possib...

Discrete Mathematics/MSQ/answer key/explanation
2023 PYQ

Let $$U = \{ 1,2,3\} $$. Let 2$$^U$$ denote the powerset of U. Consider an undirected graph G whose vertex set is 2$$^U$$. For any $$A,B \in {2^U},(A,B)$$ is an edge in G if and on...

Discrete Mathematics/NAT/explanation
2022 PYQ

Consider the following two statements with respect to the matrices A m $$\times$$ n , B n $$\times$$ m , C n$$\times$$ n and D n $$\times$$ n . Statement 1 : tr(AB) = tr(BA) Statem...

Discrete Mathematics/MCQ/answer key/explanation
2022 PYQ

Which of the following statements is/are TRUE for a group G?

Discrete Mathematics/MSQ/answer key/explanation
2022 PYQ

Consider a simple undirected graph of 10 vertices. If the graph is disconnected, then the maximum number of edges it can have is __________.

Discrete Mathematics/NAT/explanation
2022 PYQ

The number of arrangements of six identical balls in three identical bins is ___________.

Discrete Mathematics/NAT/explanation
2022 PYQ

The value of the following limit is _____________. $$\mathop {\lim }\limits_{x \to {0^ + }} {{\sqrt x } \over {1 - {e^{2\sqrt x }}}}$$

Discrete Mathematics/NAT/explanation
2022 PYQ

Which one of the following is the closed form for the generating function of the sequence (a n } n $$\ge$$ 0 defined below? $${a_n} = \left\{ {\matrix{ {n + 1,} & {n\,is\,odd} \cr...

Discrete Mathematics/MCQ/answer key/explanation
2022 PYQ

Consider a simple undirected unweighted graph with at least three vertices. If A is the adjacency matrix of the graph, then the number of 3-cycles in the graph is given by the trac...

Discrete Mathematics/MCQ/answer key/explanation
2022 PYQ

Consider solving the following system of simultaneous equations using LU decomposition. x 1 + x 2 $$-$$ 2x 3 = 4 x 1 + 3x 2 $$-$$ x 3 = 7 2x 1 + x 2 $$-$$ 5x 3 = 7 where L and U ar...

Discrete Mathematics/MCQ/answer key/explanation
2022 PYQ

Consider a simple undirected weighted graph G, all of whose edge weights are distinct. Which of the following statements about the minimum spanning trees of G is/are TRUE?

Discrete Mathematics/MSQ/answer key/explanation
2022 PYQ

Which of the properties hold for the adjacency matrix A of a simple undirected unweighted graph having n vertices?

Discrete Mathematics/MCQ/answer key/explanation
2022 PYQ

Which of the following is/are the eigenvector(s) for the matrix given below? $$\left( {\matrix{ { - 9} & { - 6} & { - 2} & { - 4} \cr { - 8} & { - 6} & { - 3} & { - 1} \cr {20} & {...

Discrete Mathematics/MSQ/answer key/explanation
2021 PYQ

Let p and q be two propositions. Consider the following two formulae in propositional logic. S 1 : (¬p ∧ (p ∨ q)) → q S 2 : q → (¬p ∧ (p ∨ q)) Which one of the following choices is...

Discrete Mathematics/MCQ/answer key/explanation
2021 PYQ

There are 6 jobs with distinct difficulty levels, and 3 computers with distinct processing speeds. Each job is assigned to a computer such that: - The fastest computer gets the tou...

Discrete Mathematics/NAT/explanation
2021 PYQ

Consider the two statements. S 1 : There exist random variables X and Y such that (E[X - E(X)) (Y - E(Y))]) 2 > Var[X] Var[Y] S 2 : For all random variables X and Y, Cov[X, Y] = E...

Discrete Mathematics/STMT/answer key/explanation
2021 PYQ

A relation R is said to be circular if a R b and b R c together imply c R a. Which of the following options is/are correct?

Discrete Mathematics/MSQ/answer key/explanation