# Discrete Mathematics MCQs

## MCQs on Discrete Mathematics

Solve Discrete Mathematics Multiple-Choice Questions to prepare better for GATE. If you wish to learn more about Discrete Mathematics and Discrete Mathematics MCQs, you can check notes, mock tests, and previous years’ question papers. Gauge the pattern of MCQs on Discrete Mathematics by solving the ones that we have compiled below for your practice:

## Discrete Mathematics Multiple-Choice Questions

1. Consider x ∈ N where x is prime. Here, x is a ________ set.

a. Empty

b. Infinite

c. Finite

d. Not a set

2. Convert a set x in the roster form, where the set x consists of the positive prime number that divides 72.

a. {3, 5, 7}

b. {2, 3, 7}

c. {2, 3}

d. {∅}

3. _____________ is the intersection of the two sets {1, 2, 8, 9, 10, 5} and {1, 2, 6, 10, 12, 15}.

a. sd) {1, 6, 12, 9, 8}

b. {2, 5, 10, 9}

c. {5, 6, 12, 15}

d. {1, 2, 10}

4. If n(P) = 20 and n(Q) = 30 and n(P U Q) = 40 then n(P ∩ Q) is:

a. 10

b. 20

c. 30

d. 40

5. Which of these can be taken as discrete objects?

a. Rational numbers

b. Integers

c. People

d. All of the above

Answer: (d) All of the above

6. If the functions g and f are onto functions, then the function (gof) is _________ function:

a. onto

b. one to one

c. one-to-many

d. Into

7. If set P consists of 4 elements and set Q consists of 5 elements, then how many injections can we define from set P to set Q?

a. 144

b. 120

c. 64

d. 24

8. Total number of bytes needed to encode 2000 bits of data:

a. 8 Byte

b. 4 bytes

c. 5 bytes

d. 2 bytes

9. The cardinality of a less than 20 even positive integers set is:

a. 12

b. 9

c. 10

d. 8

10. If P = {2, 8, 12, 15, 16} and Q = {8, 16, 15, 18, 9}, then the union of P and Q is ___________.

a. {2, 8, 9, 12, 15, 16, 18}

b. {8, 16, 15, 18, 9}

c. {2, 8, 12, 15, 16}

d. {8, 16, 15}

Answer: (a) {2, 8, 9, 12, 15, 16, 18}

11. Consider two positive numbers a and b less than one, where the maximum values of Ceil(a+b) and Floor(a+b) is:

a. Ceil(a+b) is 1 and Floor(a+b) is 2

b. Ceil(a+b) is 2 and Floor(a+b) is 1

c. Ceil(a+b) is 0 and Floor(a+b) is 1

d. Ceil(a+b) is 1 and Floor(a+b) is 0

Answer: (b) Ceil(a+b) is 2 and Floor(a+b) is 1

12. What is the negation of the “1001011” bits?

a. 0110100

b. 1100100

c. 10110100

d. 11011011

13. If the bits of Y = 100110 and the bits of X = 001101, then the output of the X (Ex-or) Y will be:

a. 101011

b. 1101010

c. 101000

d. 0010101

14. Which of these Law of Boolean would prove the X.X=X:

a. Idempotent Law

b. Complement Law

c. Double Complement Law

d. Identity Law

15. Which of these conditions is apt if one wants to add two matrices?

a. Columns of both of those matrices that we would add are equal.

b. The columns and rows of the matrices that we want to add are similar.

c The total number of the rows of the first matrix must be equal to the total number of columns in the second matrix that we want to add.

d. The rows of both of those matrices that we would add are similar.

Answer: (a) Columns of both of those matrices that we would add are equal.

16. _____________ is the Universal logic gate:

a. AND

b. NAND

c. NOT

d. OR

17. For a Boolean Expression, the canonical forms have _______ types.

a. Four

b. Three

c. Five

d. Two

18. In complexity theory, which case does NOT exist?

a. Worst Case

b. Best Case

c. Null Case

d. Average Case

19. The primary use of the Boolean algebra is ____________:

a. to design the digital computers

b. in circuit theory

c. to build the logic symbols

d. to build algebraic functions

Answer: (a) to design the digital computers

20. The _______________ search compares every element against the searching element until it is not found:

a. Binary

b. Merge

c. Sequential

d. none of the above