Explore topic-wise MCQs in Discrete Mathematics.

This section includes 91 Mcqs, each offering curated multiple-choice questions to sharpen your Discrete Mathematics knowledge and support exam preparation. Choose a topic below to get started.

1.

A monoid is called a group if _______a) (a*a)=a=(a+c)b) (a*c)=(a+c)c) (a+c)=ad) (a*c)=(c*

A. (a*a)=a=(a+c)
B. (a*c)=(a+c)c) (a+c)=ad) (a*
C. (a*c)=(a+c)c) (a+c)=a
D. (a*c)=(c*a)=e
Answer» E.
2.

Condition for monoid is __________a) (a+e)=ab) (a*e)=(a+e)c) a=(a*(a+e)d) (a*e)=(e*

A. (a+e)=a
B. (a*e)=(a+e)
C. a=(a*(a+e)
D. (a*
Answer» E.
3.

Consider an integer 23 such that 23 >= 3p for a 2p-cycle in a permutation group, then p is ___________

A. odd prime
B. even prime
C. rational number
D. negative prime
Answer» B. even prime
4.

A semigroup S under binary operation * that has an identity is called __________

A. multiplicative identity
B. monoid
C. subgroup
D. homomorphism
Answer» C. subgroup
5.

a * H is a set of _____ coset.

A. right
B. left
C. sub
D. semi
Answer» C. sub
6.

Suppose that H be an X-set and suppose that a∼b and |Xₐ|=|Xᵦ|, the which of the following is true?

A. Xₐ is powerset of Xᵦ
B. Xₐ is isomorphic to Xᵦ
C. Xₐ is homomorphic to Xᵦ
D. Xᵦ is the subset of Xₐ
Answer» C. Xₐ is homomorphic to Xᵦ
7.

_______ characterizes the properties of distributive lattices.

A. Congruence Extension Property
B. Algebraic extension property
C. Poset
D. Semigroup
Answer» C. Poset
8.

If the 4 sides of a square are to be colored by colors. How many different colourings with 50 colours are there if two arrangements that can be obtained from each other by rotation are identical?

A. 773762
B. 363563
C. 4536822
D. 1563150
Answer» E.
9.

What is an irreducible module?

A. A cyclic module in a ring with any non-zero element as its generator
B. A cyclic module in a ring with any positive integer as its generator
C. An acyclic module in a ring with rational elements as its generator
D. A linearly independent module in a semigroup with a set of real numbers
Answer» B. A cyclic module in a ring with any positive integer as its generator
10.

The order of a simple abelian group is __________

A. infinite
B. real number
C. finite
D. prime
Answer» B. real number
11.

Let (z, *) is a group with x*y=x+y-2 then inverse of x is ___________

A. -(x+4)
B. (x²+6)
C. (x+y)/5
D. (3y+4x²)
Answer» B. (x²+6)
12.

A trivial subgroup consists of ___________

A. Identity element
B. Coset
C. Inverse element
D. Ring
Answer» B. Coset
13.

What is a circle group?

A. a subgroup complex numbers having magnitude 1 of the group of nonzero complex elements
B. a subgroup rational numbers having magnitude 2 of the group of real elements
C. a subgroup irrational numbers having magnitude 2 of the group of nonzero complex elements
D. a subgroup complex numbers having magnitude 1 of the group of whole numbers
Answer» B. a subgroup rational numbers having magnitude 2 of the group of real elements
14.

How many indistinguishable necklaces can be made from beads of 4 colors with exactly 9 beads of each color where each necklace is of length 16?

A. 76967234
B. 5652209
C. 14414400
D. 8686214
Answer» D. 8686214
15.

Let K be a group with 8 elements. Let H be a subgroup of K and H

A. 8
B. 2
C. 3
D. 4
Answer» E.
16.

_____ is the multiplicative identity of natural numbers.

A. 0
B. -1
C. 1
D. 2
Answer» D. 2
17.

A function is defined by f(x)=2x and f(x + y) = f(x) + f(y) is called _____________

A. isomorphic
B. homomorphic
C. cyclic group
D. heteromorphic
Answer» B. homomorphic
18.

Condition of semigroup homomorphism should be ____________

A. f(x * x) = f(x * y)
B. f(x) = f(y)
C. f(x) * f(y) = f(y)
D. f(x * y) = f(x) * f(y)
Answer» E.
19.

A function defined by f(x)=2*x such that f(x+y)=2x+y under the group of real numbers, then ________

A. Isomorphism exists
B. Homomorphism exists
C. Heteromorphic exists
D. Association exists
Answer» C. Heteromorphic exists
20.

A normal subgroup is ____________

A. a subgroup under multiplication by the elements of the group
B. an invariant under closure by the elements of that group
C. a monoid with same number of elements of the original group
D. an invariant equipped with conjugation by the elements of original group
Answer» E.
21.

An isomorphism of Boolean algebra is defined as _______

A. order isomorphism
B. unordered isomorphism
C. order homomorphism
D. hyper-morphism
Answer» B. unordered isomorphism
22.

The number of generators of cyclic group of order 219 is __________

A. 144
B. 124
C. 56
D. 218
Answer» B. 124
23.

Let X be a n-square matrix such that Y = X + 8I. Which of the following property will exist?

A. idempotent
B. Y transpose is nilpotent
C. X nilpotent
D. Y inverse
Answer» C. X nilpotent
24.

If the sum of elements in each row of an n×n matrix Z is zero, then the matrix is ______________

A. inverse
B. non-singular
C. additive inverse
D. singular
Answer» E.
25.

Lagrange’s theorem specifies __________

A. the order of semigroup is finite
B. the order of the subgroup divides the order of the finite group
C. the order of an abelian group is infinite
D. the order of the semigroup is added to the order of the group
Answer» C. the order of an abelian group is infinite
26.

The set of even natural numbers, {6, 8, 10, 12,..,} is closed under addition operation. Which of the following properties will it satisfy?

A. closure property
B. associative property
C. symmetric property
D. identity property
Answer» B. associative property
27.

A group G, ({0}, +) under addition operation satisfies which of the following properties?

A. identity, multiplicity and inverse
B. closure, associativity, inverse and identity
C. multiplicity, associativity and closure
D. inverse and closure
Answer» C. multiplicity, associativity and closure
28.

Let G be a finite group with two sub groups M & N such that |M|=56 and |N|=123. Determine the value of |M⋂N|.

A. 1
B. 56
C. 14
D. 78
Answer» B. 56
29.

A set of representatives of all the cosets is called _________

A. transitive
B. reversal
C. equivalent
D. transversal
Answer» E.
30.

Minimum subgroup of a group is called _____________

A. a commutative subgroup
B. a lattice
C. a trivial group
D. a monoid
Answer» D. a monoid
31.

If a * b = a such that a ∗ (b ∗ c) = a ∗ b = a and (a * b) * c = a * b = a then ________

A. * is associative
B. * is commutative
C. * is closure
D. * is abelian
Answer» B. * is commutative
32.

A subgroup has the properties of ________

A. Closure, associative
B. Commutative, associative, closure
C. Inverse, identity, associative
D. Closure, associative, Identity, Inverse
Answer» E.
33.

Consider the set B* of all strings over the alphabet set B = {0, 1} with the concatenation operator for strings ________

A. does not form a group
B. does not have the right identity element
C. forms a non-commutative group
D. forms a group if the empty string is removed from
Answer» B. does not have the right identity element
34.

Suppose Kₘ={P∈Sₘ|, |P| is odd prime}. Determine the set for which m≥3 Kₘ a subgroup of Sₘ.

A. {3, 5, 7, 11, 13, …}
B. {-14, -8, -3, 0, 3, 8, 14}
C. {2, 4, 6, 8, 10, 12}
D. {12, 25, 56, 78, 134,…}
Answer» B. {-14, -8, -3, 0, 3, 8, 14}
35.

All the rings of order p2 is ____________

A. associative
B. cyclic
C. inverse
D. commutative
Answer» E.
36.

If Y⁹⁸ (a raised to the power of 5) = 0 and Y is a 97-square matrix. Determine the value of Y⁹⁷.

A. I+Y
B. -Y+3
C. 0
D.
Answer» D. Y²
37.

a * H = H * a relation holds if __________

A. H is semigroup of an abelian group
B. H is monoid of a group
C. H is a cyclic group
D. H is subgroup of an abelian group
Answer» E.
38.

If F is a free semigroup on a set S, then the concatenation of two even words is ________

A. a semigroup of F
B. a subgroup of F
C. monoid of F
D. cyclic group of F
Answer» C. monoid of F
39.

If X is an idempotent nonsingular matrix, then X must be ___________

A. singular matrix
B. identity matrix
C. idempotent matrix
D. nonsingular matrix
Answer» C. idempotent matrix
40.

In a group there must be only __________ element.

A. 1
B. 2
C. 3
D. 5
Answer» B. 2
41.

An element of a commutative ring R(1≠0) is nilpotent if __________

A. a+1=0
B. aⁿ = 0, for some positive integer n
C. aⁿ = 1, for some integer n
D. a² = 0
Answer» C. aⁿ = 1, for some integer n
42.

B₁: ({0, 1, 2….(n-1)}, xₘ) where xₘ stands for “multiplication-modulo-n” and B₂: ({0, 1, 2….n}, xₙ) where xₙ stands for “multiplication-modulo-m” are the two statements. Both B₁ and B₂ are considered to be __________

A. groups
B. semigroups
C. subgroups
D. associative subgroup
Answer» C. subgroups
43.

The group of matrices with determinant _________ is a subgroup of the group of invertible matrices under multiplication.

A. 2
B. 3
C. 1
D. 4
Answer» D. 4
44.

A function f:(M,∗)→(N,×) is a homomorphism if ______

A. f(a, b) = a*b
B. f(a, b) = a/b
C. f(a, b) = f(a)+f(b)
D. f(a, b) = f(a)*f(a)
Answer» C. f(a, b) = f(a)+f(b)
45.

The dihedral group having order 6 can have degree _____________

A. 3
B. 26
C. 326
D. 208
Answer» B. 26
46.

If (M, *) is a cyclic group of order 73, then number of generator of G is equal to ______

A. 89
B. 23
C. 72
D. 17
Answer» D. 17
47.

An infinite cyclic group does not have a ______ series.

A. AP
B. GP
C. Composite
D. Finite
Answer» D. Finite
48.

Suppose, M is a lower triangular matrix with all diagonal entries zero. The resultant matrix of M+I will be ___________

A. idempotent
B. singular
C. nilpotent
D. inverse
Answer» C. nilpotent
49.

Let H be a finite group. The order of Sylow p-subgroup of H for every prime factor p with multiplicity 9 is?

A. p+6
B. p⁹
C. pᵖ
D. 3!*p²
Answer» C. pᵖ
50.

Every cyclic group is a/an ______

A. infinite subgroup
B. abelian group
C. monoid
D. commutative semigroup
Answer» C. monoid