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.
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
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
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
5.

Onto function are known as injection.

A. True
B. False
Answer» C.
6.

For an onto function range is equivalent to codomain.

A. True
B. False
Answer» B. False
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
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!
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
10.

An injection is a function which is?

A. many-one
B. one-one
C. onto
D. none of the mentioned
Answer» C. onto
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
12.

State_True_or_False.$

A.
B. True
Answer» C.
13.

A function is defined by mapping f : A -> B such that A contains m elements and B contains n elements and 1‚â§n‚â§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>
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
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
16.

A function is defined by mapping f : A -> B such that A contains m elements and B contains n elements and m ‚â§ 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!
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.
18.

An injection is a function which is :

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