Top 350+ Solved Discrete Mathematics MCQ Questions Answer
Q. If R be relation ‘<‘ from A = {1, 2, 3, 4} to B = {1, 3, 5} ie, (a, b) Î R iff a < b, then RoR– 1 is
a. {(1, 3), (1, 5), (2, 3), (2, 5), (3, 5), (4, 5)}
b. {(3, 1), (5, 1), (3, 2), (5, 2), (5, 3), (5, 4)}
c. {(3, 3), (3, 5), (5, 3), (5, 5)}
d. { (3, 3), (3, 4), (4, 5)}
Q. R is a relation from {11, 12, 13} to {8, 10, 12} defined by y = x – 3. The relation R – 1 is
a. {(11, 8), (13, 10)}
b. {(8, 11), (10, 13)}
c. {(8, 11), (9, 12), (10, 13)}
d. none of the above
Q. R is a relation on N given by N = {(x, y): 4x + 3y = 20}. Which of the following belongs to R?
a. (– 4, 12)
b. (5, 0)
c. (3, 4)
d. (2, 4)
Q. The relation R defined on the set of natural numbers as {(a, b): a differs from b by 3} is given
a. {(1, 4), (2, 5), (3, 6), ….}
b. { (4, 1), (5, 2), (6, 3), ….}
c. {(4, 1), (5, 2), (6, 3), ….}
d. none of the above
Q. Let R = { ( 3, 3 ) ( 6, 6 ) ( ( 9, 9 ) ( 12, 12 ), ( 6, 12 ) ( 3, 9 ) ( 3, 12 ), ( 3, 6 ) } be a relation on the set A = { 3, 6, 9, 12 }. The relation is
a. reflexive and transitive
b. reflexive only
c. an equivalence relation
d. reflexive and symmetric only
Q. Which of the following statement is a proposition?
a. get me a glass of milkshake
b. god bless you!
c. what is the time now?
d. the only odd prime number is 2
Q. Let P (x) denote the statement “x >7.” Which of these have truth value true?
a. p (0)
b. p (4)
c. p (6)
d. p (9)
Q. ”Everyone wants to learn cosmology.” This argument may be true for which domains?
a. all students in your cosmology class
b. all the cosmology learning students in the world
c. both of the mentioned
d. none of the mentioned
Q. Let T (x, y) mean that student x likes dish y, where the domain for x consists of all students at your school and the domain for y consists of all dishes. Express ¬T (Amit, South Indian) by a simple English sentence.
a. all students does not like south indian dishes.
b. amit does not like south indian people.
c. amit does not like south indian dishes.
d. amit does not like some dishes.
Q. Which rule of inference is used in each of these arguments, “If it is Wednesday, then the Smartmart will be crowded. It is Wednesday. Thus, the Smartmart is crowded.”
a. modus tollens
b. modus ponens
c. disjunctive syllogism
d. simplification
Q. Which rule of inference is used in each of these arguments, “If it hailstoday, the local office will be closed. The local office is not closed today. Thus, it did not hailed today.”
a. modus tollens
b. conjunction
c. hypothetical syllogism
d. simplification
Q. Which rule of inference is used, ”Bhavika will work in an enterprise this summer. Therefore, this summer Bhavika will work in an enterprise or he will go to beach.”
a. simplification
b. conjunction
c. addition
d. disjunctive syllogism
Q. What rules of inference are used in this argument?“All students in this science class has taken a course in physics” and “Marry is a student in this class” imply the conclusion “Marry has taken a course in physics.”
a. universal instantiation
b. universal generalization
c. existential instantiation
d. existential generalization