9th class Math, Chapter 8: Logic MCQs

1. Which of the following expressions is often related to inductive reasoning?

1. (A) based on repeated experiments ✓
2. (B) if and only if statements
3. (C) statement is proven by a theorem
4. (D) based on general principles

2. Which of the following sentences describe deductive reasoning?

1. (A) general conclusions from a limited number of observations
2. (B) based on repeated experiments
3. (C) based on units of information that are accurate
4. (D) draw conclusion from well-known facts ✓

3. Which one of the following statements is true?

1. (A) The set of integers is finite
2. (B) The sum of the interior angles of any quadrilateral is always 180°
3. (C) 22/7 ∉ Q' ✓
4. (D) All isosceles triangles are equilateral triangles

4. Which of the following statements is the best to represent the negation of the statement "The stove is burning"?

1. (A) the stove is not burning ✓
2. (B) the stove is dim
3. (C) the stove is turned to low heat
4. (D) it is both burning and not burning

5. The conjunction of two statements p and q is true when:

1. (A) both p and q are false
2. (B) both p and q are true ✓
3. (C) only q is true
4. (D) only p is true

6. A conditional is regarded as false only when:

1. (A) antecedent is true and consequent is false ✓
2. (B) consequent is true and antecedent is false
3. (C) antecedent is true only
4. (D) consequent is false only

7. The contrapositive of q → p is:

1. (A) q → ~p
2. (B) ~q → p
3. (C) ~p → ~q ✓
4. (D) ~q → ~p

8. The statement "Every integer greater than 2 is a sum of two prime numbers" is:

1. (A) theorem
2. (B) conjecture ✓
3. (C) axiom
4. (D) postulates

9. The statement "A straight line can be drawn between any two points" is:

1. (A) theorem
2. (B) conjecture
3. (C) axiom ✓
4. (D) logic

10. The statement "The sum of the interior angles of a triangle is 180°" is a:

1. (A) converse
2. (B) theorem ✓
3. (C) axiom
4. (D) conditional

11. A sentence which is either true or false but not both is called:

1. (A) a conjecture
2. (B) an axiom
3. (C) a theorem
4. (D) a statement ✓

12. Drawing general conclusions from a limited number of observations is called:

1. (A) induction ✓
2. (B) deduction
3. (C) conjunction
4. (D) negation

13. Drawing conclusions from premises believed to be true is called:

1. (A) induction
2. (B) implication
3. (C) negation
4. (D) deduction ✓

14. The symbol ~p is read as:

1. (A) if p then q
2. (B) not p ✓
3. (C) p and q
4. (D) p or q

15. The symbol ∨ stands for:

1. (A) or ✓
2. (B) and
3. (C) if … then
4. (D) if and only if

16. The symbol ∧ stands for:

1. (A) implies
2. (B) and ✓
3. (C) or
4. (D) not

17. If p is true then ~p is:

1. (A) true
2. (B) undecided
3. (C) equal to p
4. (D) false ✓

18. The disjunction p ∨ q is false only when:

1. (A) both p and q are false ✓
2. (B) both p and q are true
3. (C) p is true and q is false
4. (D) p is false and q is true

19. In a conditional p → q the statement p is called the:

1. (A) consequent
2. (B) converse
3. (C) contrapositive
4. (D) antecedent (hypothesis) ✓

20. The biconditional p ↔ q is true when:

1. (A) q is true only
2. (B) p and q have different truth values
3. (C) p and q have the same truth value ✓
4. (D) p is true only