Explore topic-wise MCQs in Discrete Mathematics.

This section includes 18 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 bijection is a function which is many-one and onto.

A. True
B. False
Answer» C.
Discussion
2.

A function is defined by mapping f:A→B such that A contains m elements and B contains n elements and m > n then number of bijections are ________

A. nCm x m!
B. nCm x n!
C. 0
D. none of the mentioned
Answer» D. none of the mentioned
Discussion
3.

A function is defined by mapping f : A → B such that A contains m elements and B contains n elements and 1≤n≤m then number of onto functions are ________

A. r=1∑r=n nCr (-1)n-r rm
B. r=1∑r=n nCr (-1)n-r rn
C. r=1∑r=n nCr (-1)m-r rn
D. None of the mentioned
Answer» B. r=1∑r=n nCr (-1)n-r rn
Discussion
4.

Set A has 3 elements and set B has 4 elements then number of injections defined from A to B are?

A. 12
B. 24
C. 36
D. 48
Answer» C. 36
Discussion
5.

Onto function are known as injection.

A. True
B. False
Answer» C.
Discussion
6.

For an onto function range is equivalent to codomain.

A. True
B. False
Answer» B. False
Discussion
7.

A function is defined by mapping f : A -> B such that A contains m elements and B contains n elements and m>n then number of one one functions are ________

A. nCm x m!
B. nCm x n!
C. 0
D. none of the mentioned
Answer» D. none of the mentioned
Discussion
8.

A function is defined by mapping f : A → B such that A contains m elements and B contains n elements and m ≤ n then number of one one functions are _________

A. nCm x m!
B. nCm x n!
C. 0
D. none of the mentioned
Answer» B. nCm x n!
Discussion
9.

A mapping f : X → Y is one one if __________

A. f(x1) ≠ f(x2) for all x1, x2 in X
B. If f(x1) = f(x2) then x1 = x2 for all x1, x2 in X
C. f(x1) = f(x2) for all x1, x2 in X
D. None of the mentioned
Answer» C. f(x1) = f(x2) for all x1, x2 in X
Discussion
10.

An injection is a function which is?

A. many-one
B. one-one
C. onto
D. none of the mentioned
Answer» C. onto
Discussion
11.

A_FUNCTION_IS_DEFINED_BY_MAPPING_F:A->B_SUCH_THAT_A_CONTAINS_M_ELEMENTS_AND_B_CONTAINS_N_ELEMENTS_AND_M_>_N_THEN_NUMBER_OF_BIJECTIONS_ARE_:?$

A. <sup>n</sup>C<sub>m</sub> x m!
B. <sup>n</sup>C<sub>m</sub> x n!
C. 0
D. none of the mentioned
Answer» D. none of the mentioned
Discussion
12.

State_True_or_False.$

A.
B. True
Answer» C.
Discussion
13.

A function is defined by mapping f : A -> B such that A contains m elements and B contains n elements and 1≤n≤m then number of onto functions are?#

A. <sub>r=1</sub>‚àë<sup>r=n</sup> <sup>n</sup>C<sub>r</sub> (-1)<sup>n-r</sup> r<sup>m</sup>
B. <sub>r=1</sub>‚àë<sup>r=n</sup> <sup>n</sup>C<sub>r</sub> (-1)<sup>n-r</sup> r<sup>n</sup>
C. <sub>r=1</sub>‚àë<sup>r=n</sup> <sup>n</sup>C<sub>r</sub> (-1)<sup>m-r</sup> r<sup>n</sup>
D. None of the mentioned
Answer» B. <sub>r=1</sub>‚Äö√Ñ√∂‚àö‚Ć‚àö¬¥<sup>r=n</sup> <sup>n</sup>C<sub>r</sub> (-1)<sup>n-r</sup> r<sup>n</sup>
Discussion
14.

Set A has 3 elements and set B has 4 elements then number of injections defined from A to B are?

A. 12
B. 24
C. 36
D. 48
Answer» C. 36
Discussion
15.

A function is defined by mapping f : A -> B such that A contains m elements and B contains n elements and m>n then number of one one functions are :

A. <sup>n</sup>C<sub>m</sub> x m!
B. <sup>n</sup>C<sub>m</sub> x n!
C. 0
D. none of the mentioned
Answer» D. none of the mentioned
Discussion
16.

A function is defined by mapping f : A -> B such that A contains m elements and B contains n elements and m ≤ n then number of one one functions are :$

A. <sup>n</sup>C<sub>m</sub> x m!
B. <sup>n</sup>C<sub>m</sub> x n!
C. 0
D. none of the mentioned
Answer» B. <sup>n</sup>C<sub>m</sub> x n!
Discussion
17.

A mapping f : X -> Y is one one if :

A. f(x<sub>1</sub>) ≠ f(x<sub>2</sub>) for all x<sub>1</sub>, x<sub>2</sub> in X.
B. If f(x<sub>1</sub>) = f(x<sub>2</sub>) then x<sub>1</sub> = x<sub>2</sub> for all x<sub>1</sub>, x<sub>2</sub> in X.
C. f(x<sub>1</sub>) = f(x<sub>2</sub>) for all x<sub>1</sub>, x<sub>2</sub> in X.
D. None of the mentioned
Answer» C. f(x<sub>1</sub>) = f(x<sub>2</sub>) for all x<sub>1</sub>, x<sub>2</sub> in X.
Discussion
18.

An injection is a function which is :

A. many-one
B. one-one
C. onto
D. none of the mentioned
Answer» C. onto
Discussion