Engineering-Mathematics
Question 1 |
where tr() represents the trace of a matrix. Which one of the following holds?
A | Statement 1 is correct and Statement 2 is wrong. |
B | Statement 1 is wrong and Statement 2 is correct. |
C | Both Statement 1 and Statement 2 are correct. |
D | Both Statement 1 and Statement 2 are wrong. |
(In exam point of view, you can just consider small example and conclude).
So trace of AB = trace of BA
As well
Trace of CD = trace of DC
Question 2 |
A | ![]() |
B | ![]() |
C | If the order of G is 2 , then G is commutative. |
D | If G is commutative, then a subgroup of G need not be commutative. |
(B) : False. In a multiple instance graph, a cycle always does not indicate deadlock.
(C) : False. Unsafe state may or may not lead to deadlock.
(D) : True. Since every edge is allocated, that means there are no requests. Hence, cycle is not possible.
Question 3 |
A | 36 |
Given 10 vertices,
Then we can have a complete graph with 9 vertices and one isolated verted.
Number of edges in complete graph with 9 edges is n(n-1)/2 = 9*8/2 = 36
Question 4 |
A | 7 |
As no other condition is given,
We need to consider that distinct distribution will be based on the count of balls.
6 identical balls into 3 identical bins.
That can be done in the combination of
[6,0,0], [5,1,0], [ 4,2,0], [3,3,0], [4,1,1],[3,2,1],[2,2,2]
I.e. in 7 ways
Question 5 |

A | 1/2 |
When 0 is substituted, we get 0/0
Apply L- Hospital rule
-1/2
Question 6 |

A | |
B | |
C | |
D | |

Question 7 |
A | A ^3 |
B | A^ 3 divided by 2 |
C | A ^3 divided by 3 |
D | A ^3 divided by 6 |
Question 8 |

A | ![]() |
B | ![]() |
C | ![]() |
D | ![]() |
Given,
(Assume x1,x2,x3 as a,b,c)

Question 9 |
Which of the following statements is/are TRUE?
A | The chromatic number of the graph is 3. |
B | The graph has a Hamiltonian path |
C | The following graph is isomorphic to the Peterson graph. |
D | The size of the largest independent set of the given graph is 3. (A subset of vertices of a graph form an independent set if no two vertices of the subset are adjacent.) |
Peterson graph ihas hamiltonian path but not hamiltonian cycle
Given graph in option C is isomorphic as the given has same number of vertice, edges, degree sequence and cycles.
LArgest independent set can be more than 3
Question 10 |
A | The diagonal entries of A 2 are the degrees of the vertices of the graph. |
B | If the graph is connected, then none of the entries of A^ n + 1 + I n can be zero. |
C | If the sum of all the elements of A is at most 2( n- 1), then the graph must be acyclic. |
D | If there is at least a 1 in each of A ’s rows and columns, then the graph must be Connected. |
The entries aii show the number of 2-length paths between the nodes i and j. Why this happens is easy to see: if there is an edge ij and an edge jk, then there will be a path ik through j. The entries ii are the degrees of the nodes i.
Similarly in A^3 we have the entries aii that show the number of 3-length paths between the nodes i and j.
In A^n-1 + I n, we will have at least n-1 length paths, so there is no possibility of zero entires
Question 11 |

A | ![]() |
B | ![]() |
C | ![]() |
D | ![]() |

Question 12 |
Let A and B be real symmetric matrices of size n × n. Then which one of the following is true?
A | AA′ = 1 |
B | A = A-1 |
C | AB = BA |
D | (AB)' = BA |

Question 13 |
Backward Euler method for solving the differential equation dy/dx = f(x,y) is specified by, (choose one of the following).
A | yn+1 = yn + hf(xn, yn) |
B | yn+1 = yn + hf(xn+1, yn+1) |
C | yn+1 = yn-1 + 2hf(xn, yn) |
D | yn+1 = (1 + h) f(xn+1, yn+1) |
With initial value y(x0) = y0. Here the function f and the initial data x0 and y0 are known. The function y depends on the real variable x and is unknown. A numerical method produces a sequence y0, y1, y2, ....... such that yn approximates y(x0 + nh) where h is called the step size.
→ The backward Euler method is helpful to compute the approximations i.e.,
yn+1 = yn + hf(x n+1, yn+1)
Question 14 |
Let A and B be any two arbitrary events, then, which one of the following is true?
A | P(A∩B) = P(A)P(B) |
B | P(A∪B) = P(A) + P(B) |
C | P(A|B) = P(A∩B)P(B) |
D | P(A∪B) ≤ P(A) + P(B) |
(B) Happens when A and B are mutually exclusive.
(C) Not happens.
(D) P(A∪B) ≤ P(A) + P(B) is true because P(A∪B) = P(A) + P(B) - P(A∩B).
Question 15 |
The number of distinct simple graphs with upto three nodes is
A | 15 |
B | 10 |
C | 7 |
D | 9 |

Question 16 |
The tank of matrix
is:
A | 0 |
B | 1 |
C | 2 |
D | 3 |

Question 17 |
Some group (G,o) is known to be abelian. Then, which one of the following is true for G?
A | g = g-1 for every g ∈ G |
B | g = g2 for every g ∈ G |
C | (goh)2 = g2oh2 for every g,h ∈ G |
D | G is of finite order |
For Abelian group, commutative also holds
i.e., (aob) = (boa)
Consider option (C):
(goh)2 = (goh)o(gog)
= (hog)o(goh)
= (ho(gog)oh)
= ((hog2)oh)
= (g2oh)oh
= g2o(hoh)
= g2oh2 [True]
Question 18 |
In a compact single dimensional array representation for lower triangular matrices (i.e all the elements above the diagonal are zero) of size n × n, non-zero elements (i.e elements of the lower triangle) of each row are stored one after another, starting from the first row, the index of the (i, j)th element of the lower triangular matrix in this new representation is:
A | i + j |
B | i + j - 1 |
C | j + i(i-1)/2 |
D | i + j(j-1)/2 |
If we assume array index starting from 1 then, ith row contains i number of non-zero elements. Before ith row there are (i-1) rows, (1 to i-1) and in total these rows has 1+2+3......+(i-1) = i(i-1)/2 elements.
Now at ith row, the jth element will be at j position.
So the index of (i, j)th element of lower triangular matrix in this new representation is
j = i(i-1)/2
Question 19 |
The number of substrings (of all lengths inclusive) that can be formed from a character string of length n is
A | n |
B | n2 |
C | n(n-1)/2 |
D | n(n+1)/2 |
n = 1
(n-1) = 2
(n-2) = 3
So, Total = n(n+1)/2
Question 20 |
On the set N of non-negative integers, the binary operation __________ is associative and non-commutative.
A | fog |
(fog)(x) = f(g(x))
It is associative, (fog)oh = fo(goh), but its usually not commutative. fog is usually not equal to gof.
Note that if fog exists then gof might not even exists.
Question 21 |
Amongst the properties {reflexivity, symmetry, anti-symmetry, transitivity} the relation R = {(x,y) ∈ N2 | x ≠ y } satisfies __________.
A | symmetry |
It is symmetric as if xRy then yRx.
It is not antisymmetric as xRy and yRx are possible and we can have x≠y.
It is not transitive as if xRy and yRz then xRz need not be true. This is violated when x=x.
So, symmetry is the answer.
Question 22 |
The number of subsets {1, 2, ... n} with odd cardinality is __________.
A | 2n-1 |
And so, no. of subsets with odd cardinality is half of total no. of subsets = 2n /n = 2n-1
Question 23 |
The number of edges in a regular graph of degree d and n vertices is _________.
A | d*n/2 |
d * n = 2 * |E|
∴ |E| = d*n/2
Question 24 |
The probability of an event B is P1. The probability that events A and B occur together is P2 while the probability that A and
occur together is P3. The probability of the event A in terms of P1, P2 and P3 is __________.
A | P2 + P3 |
P3 = P(A) - P2
P(A) = P2 + P3
Question 25 |
Let A, B and C be independent events which occur with probabilities 0.8, 0.5 and 0.3 respectively. The probability of occurrence of at least one of the event is __________
A | 0.93 |
Since all the events are independent, so we can write
P(A∪B∪C) = P(A) + P(B) + P(C) - P(A)P(B) - P(B)P(C) - P(A)P(C) + P(A)P(B) P(C)
= 0.8 + 0.5 + 0.3 - 0.4 - 0.5 - 0.24 + 0.12
= 0.93
Question 26 |
The Hasse diagrams of all the lattices with up to four elements are __________ (write all the relevant Hasse diagrams).
A | ![]() |
We can't draw lattice with 1 element.
For 2 element:

For 3 element:

For 4 element:
Question 27 |
Match the following items

A | (i) - (b), (ii) - (c), (iii) - (d), (iv) - (a) |
Question 28 |
Find the inverse of the matrix 
A | ![]() |
B | ![]() |
C | ![]() |
D | ![]() |
-λ3 + 2λ2 - 2 = 0
Using Cayley-Hamiltonian theorem
-A3 + 2A2 - 2I = 0
So, A-1 = 1/2 (2A - A2)
Solving we get,
Question 29 |
Let p and q be propositions. Using only the truth table decide whether p ⇔ q does not imply p → q is true or false.
A | True |
B | False |

So, "imply" is False making "does not imply" True.
Question 30 |
(a) Let * be a Boolean operation defined as
If C = A * B then evaluate and fill in the blanks:
(i) A * A = _______
(ii) C * A = _______
(b) Solve the following boolean equations for the values of A, B and C:
![]()
A | Theory Explanation. |
Question 31 |
A 3-ary tree is a tree in which every internal node has exactly three children. Use induction to prove that the number of leaves in a 3-ary tree with n interval nodes is 2(n-1)+3.
A | Theory Explanation. |
Question 32 |
Every element a of some ring (R,+,0) satisfies the equation aoa = a.
Decide whether or not the ring is commutative.
A | Theory Explanation. |
Question 33 |
Let G be a group of 35 elements. Then the largest possible size of a subgroup of G other than G itself is ______.
A | 7 |
If ‘H” is a subgroup of finite group (G,*) then O(H) is the divisor of O(G).
Given that the order of group is 35. Its divisors are 1,5,7,35.
It is asked that the size of largest possible subgroup other than G itself will be 7.
Question 34 |
Let R be the set of all binary relations on the set {1,2,3}. Suppose a relation is chosen from R at random. The probability that the chosen relation is reflexive (round off to 3 decimal places) is _____.
A | 0.125 |
The number of reflexive relations is 2^(n^2-n).
The total number of relations on a set with n elements is 2^ (n^2).
The probability of choosing the reflexive relation out of set of relations is
= 2^(n^2-n) /2^ (n^2)
= 2^( n^2-n- n^2)
= 2^(-n)
Given n=3, the probability will be 2-n = ⅛ = 0.125
Question 35 |
Consider the functions
- I. e-x
II. x2-sin x
III. √(x3+1)
Which of the above functions is/are increasing everywhere in [0,1]?
A | II and III only |
B | III only |
C | II only |
D | I and III only |
I. e-x
II. f'(x) = -e-x
f'(x)<0 on the interval [0,1] so this is not an increasing function.
II. x2-sinx
f'(x) = 2x - cosx
at x=0, f'(0) = 2(0) - 1 = -1 < 0
f(x) = x2 - sinx is decreasing over some interval, increasing over some interval as cosx is periodic.
As the question is asked about increasing everywhere II is false.
III. √(x3+1) = (x3+1)1/2
f'(x) = 1/2(3x2/√(x3+1))>0
f(x) is increasing over [0,1].
Question 36 |
For n>2, let a ∈ {0,1}n be a non-zero vector. Suppose that x is chosen uniformly at random from {0,1}n. Then, the probability that is an odd number
is _____.
A | 0.5 |
‘x’ is a vector chosen randomly from {0,1}n
‘a’ can have 2(n-1) possibilities, x can have 2n possibilities.
∑aixi have (2n-1)(2n) possibilities, which is an even number of outcomes.
The probability of https://solutionsadda.in/wp-content/uploads/2020/02/41.jpg is odd is ½.
For example:
Take n=3
a = {001, 010, 100, 011, 101, 111}
x = {000, 001, 010, 011, 100, 101, 110, 111}
Computed as [001]×[000] = 0+0+0 = 0 Output = even
[001]×[001] = 0+0+1 = 0 Output = odd
Similarly, there could be 28 even, 28 odd outputs for the a(size=7), x(size=8) of total 56 outputs.
Question 37 |
Graph G is obtained by adding vertex s to K3,4 and making s adjacent to every vertex of K3,4. The minimum number of colours required to edge-colour G is _____.
A | 7 |
The vertex in the set of size 3 has 4 edges connected to 4 vertices on other set. So, edge color of G is max(3,4) i.e. 4.
When a vertex is added to the graph with 7 vertices ( K3x4 has 7 vertices), there would be 7 edges associated to that new vertex. As per the edge coloring “no two adjacent edges have same color).
As the new vertex with 7 edges need to be colored with 7 colors, the edge color of graph G is 7.
Question 38 |
Which one of the following predicate formulae is NOT logically valid?
Note that W is a predicate formula without any free occurrence of x.
A | ∃x(p(x) → W) ≡ ∀x p(x) → W |
B | ∀x(p(x) → W) ≡ ∀x p(x) → W
|
C | ∃x(p(x) ∧ W) ≡ ∃x p(x) ∧ W |
D | ∀x(p(x) ∨ W) ≡ ∀x p(x) ∨ W |
~p→q ≡ ~p∨q
Demorgan laws:
~(∀x(a(x)) ≡ ∃x~a(x)
~(∃x(a(x)) ≡ ∀x~a(x)
(A) ∃x(p(x)→w) ≡ ∀x p(x)→w
LHS: ∃x(p(x)→w) ≡ ∃x(~p(x)∨w)
≡ ∃x(~p(x))∨w
Demorgan’s law:
~(∀x(a(x)) = ∃x ~ a(x)
≡ ~(∀x P(x)) ∨ w
≡ (∀x) P(x) → w ≡ RHS
It’s valid.
(B) ∀x(P(x) → w) ≡ ∀x(~P(x) ∨ w)
≡ ∀x(~P(x)) ∨ w
≡ ~(∃x P(x)) ∨ w
≡ ∃x P(x) → w
This is not equal to RHS.
(C) ∃x(P(x) ∧ w) ≡ ∃x P(x) ∧ w
‘w’ is not a term which contains x.
So the quantifier does not have any impact on ‘w’.
Thus it can be written as
∃x(P(x)) ∧ w) ≡ ∃x P(x) ∧ w
(D) ∀(x)(P(x) ∨ w) ≡ ∀x P(x) ∨ w
‘w’ is not a term which contains ‘x’.
So the quantifier does not have an impact on ‘w’.
Thus ∀(x)(P(x) ∨ w) ≡ ∀x P(x) ∨ w
Question 39 |
The number of permutations of the characters in LILAC so that no character appears in its original position, if the two L’s are indistinguishable, is _______.
A | 12 |
― ― ― ― ―
Given: L I L A C
The derangement formula ⎣n!/e⎦ cannot be directly performed as there are repeated characters.
Let’s proceed in regular manner:
The L, L can be placed in other ‘3’ places as
(1) Can be arranged such that A, I, C be placed in three positions excluding ‘C’ being placed at its own position, which we get only 2×2×1 = 4 ways.
Similarly (2) can be filled as A, I, C being placed such that 4th position is not filled by A, so we have 2×2×1 = 4 ways. Similarly with (3).
Totally, we get 4+4+4 = 12 ways.
Question 40 |
Let A and B be two n×n matrices over real numbers. Let rank(M) and det(M) denote the rank and determinant of a matrix M, respectively. Consider the following statements,
- I. rank(AB) = rank(A) rank(B)
II. det(AB) = det(A) det(B)
III. rank(A + B) ≤ rank(A) + rank(B)
IV. det(A + B) ≤ det(A) + det(B)
Which of the above statements are TRUE?
A | I and II only
|
B | I and IV only |
C | III and IV only |
D | II and III only
|
Rank is the number of independent rows(vectors) of a matrix. On product of two matrices, the combined rank is more than the sum of individual matrices (subtracted with the order n)
det(AB) = det(A)∙det(B) as the magnitude remains same for the matrices after multiplication.
Note: We can just take a 2x2 matrix and check the options.
Question 41 |
Let A and B be sets and let Ac and Bc denote the complements of the sets A and B. The set (A – B) ∪ (B - A) ∪ (A∩B) is equal to
A | A ∪ B |
B | Ac ∪ Bc |
C | A ∩ B |
D | Ac ∩ Bc |

(A - B) = 1
(B - A) = 2
(A∩B) = 3
A∪B = (1∪2∪3)
(A – B) ∪ (B - A) ∪ (A∩B) = 1∪2∪3 = (A∪B)
Question 42 |
Let X = {2,3,6,12,24}, Let ≤ be the partial order defined by X ≤ Y if x divides y. Number of edge as in the Hasse diagram of (X,≤) is
A | 3 |
B | 4 |
C | 9 |
D | None of the above |

No. of edges = 4
Question 43 |
Suppose X and Y are sets and X Y and are their respective cardinalities. It is given that there are exactly 97 functions from X to Y. from this one can conclude that
A | |X| = 1, |Y| = 97 |
B | |X| = 97, |Y| = 1 |
C | |X| = 97, |Y| = 97 |
D | None of the above |
|Y||X| = 97
→ Option A only satisfies.
Question 44 |
Which of the following statements is false?
A | The set of rational numbers is an abelian group under addition. |
B | The set of integers in an abelian group under addition. |
C | The set of rational numbers form an abelian group under multiplication. |
D | The set of real numbers excluding zero in an abelian group under multiplication. |
Question 45 |
Two dice are thrown simultaneously. The probability that at least one of them will have 6 facing up is
A | 1/36 |
B | 1/3 |
C | 25/36 |
D | 11/36 |
1 - (5/6 × 5/6) = 1 - (25/36) = 11/36
Question 46 |
The formula used to compute an approximation for the second derivative of a function f at a point X0 is
A | f(x0+h) + f(x0-h)/2 |
B | f(x0+h) - f(x0-h)/2h |
C | f(x0+h) + 2f(x0) + f(x0-h)/h2 |
D | f(x0+h) - 2f(x0) + f(x0-h)/h2 |
f(x0+h) - 2f(x0) + f(x0-h)/h2
Question 47 |
Let Ax = b be a system of linear equations where A is an m × n matrix and b is a m × 1 column vector and X is a n × 1 column vector of unknowns. Which of the following is false?
A | The system has a solution if and only if, both A and the augmented matrix [A b] have the same rank.
|
B | If m < n and b is the zero vector, then the system has infinitely many solutions. |
C | If m = n and b is non-zero vector, then the system has a unique solution. |
D | The system will have only a trivial solution when m = n, b is the zero vector and rank (A) = n. |
→ Solution can be depends on rank of matrix A and matrix [A B].
→ If rank[A] = rank[A B] then it can have solution otherwise no solution.
Question 48 |
Let R denotes the set of real numbers. Let f: R×R → R×R be a bijective function defined by f(x,y) = (x+y,x-y), The inverse function of f is given by
A | ![]() |
B | ![]() |
C | ![]() |
D | ![]() |

Question 49 |
Let R be a non-empty relation on a collection of sets defined by A R B if and only if A ∩ B = ф. Then, (pick the true statement)
A | R is reflexive and transitive |
B | R is symmetric and not transitive |
C | R is an equivalence relation |
D | R is not reflexive and not symmetric |
Now,
A ∩ B = ф
& B ∩ C = ф
But A ∩ B ≠ ф
So, R is not transitive.
A ∩ B = A, so R is not reflexive.
If A ∩ B = ф
then definitely B ∩ A = ф.
Hence, R is symmetric.
So, option (B) is true.
Question 50 |
Which of the following is false? Read ∧ as AND, ∨ as OR, ~ as NOT, → as one way implication and ↔ as two way implication.
A | ((x → y) ∧ x) → y |
B | ((x → y) ∧ (x ∧ y)) → x |
C | (x → (x ∨ ψ)) |
D | ((x ∨ y) ↔ (x → y) |
then option (D) will be False.


















