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Logical Equivalence Beginner-Intermediate Worksheet: Focus on common variations practice Logical Equivalence BEGINNER INTERMEDIATE

Level up your Logical Equivalence skills! You're at Worksheet 4 of 10 (33% through this series). This step-up challenge worksheet features 20 beginner-intermediate-level problems with a focus on common variations practice. Topics covered: logical equivalence for competitive exams, how to solve logical equivalence, logical equivalence tricks.

📝 Worksheet 4 of 10 • 20 questions • ⏱️ Estimated time: 20 minutes • 🎯 Beginner Intermediate level

What you'll learn in this worksheet:
Your progress through Logical Equivalence
Worksheet 4 of 10 (33% complete)

Question 1

Are the following two logical expressions equivalent? Expression 1: ¬(p ∧ q) Expression 2: ¬p ∨ ¬q Answer Yes or No and explain why.
Step 1: Understand what logical equivalence means
Two expressions are logically equivalent if they have the same truth value for ALL possible combinations of variables.

Step 2: Analyze the expressions
Expression 1: ¬(p ∧ q)
Expression 2: ¬p ∨ ¬q

Step 3: Apply De Morgan's Law
De Morgan's Law states: ¬(p ∧ q) ≡ ¬p ∨ ¬q
The negation of a conjunction equals the disjunction of negations.
These expressions ARE equivalent.

Verification with truth table:
p=T, q=T: ¬(T∧T)=F and ¬T∨¬T=F ✓
p=T, q=F: ¬(T∧F)=T and ¬T∨¬F=T ✓
p=F, q=T: ¬(F∧T)=T and ¬F∨¬T=T ✓
p=F, q=F: ¬(F∧F)=T and ¬F∨¬F=T ✓

Question 2

Are the following two logical expressions equivalent? Expression 1: ¬(p ∧ q) Expression 2: ¬p ∧ ¬q Answer Yes or No and explain why.
Step 1: Understand what logical equivalence means
Two expressions are logically equivalent if they have the same truth value for ALL possible combinations of variables.

Step 2: Analyze the expressions
Expression 1: ¬(p ∧ q)
Expression 2: ¬p ∧ ¬q

Step 3: Test with truth table
Testing: ¬(p ∧ q) vs ¬p ∧ ¬q
Counter-example: p=T, q=F
¬(T ∧ F) = ¬F = T
¬T ∧ ¬F = F ∧ T = F
Since they differ, they are NOT equivalent.

Question 3

Are the following two logical expressions equivalent? Expression 1: p → q Expression 2: ¬q → ¬p Answer Yes or No and explain why.
Step 1: Understand what logical equivalence means
Two expressions are logically equivalent if they have the same truth value for ALL possible combinations of variables.

Step 2: Analyze the expressions
Expression 1: p → q
Expression 2: ¬q → ¬p

Step 3: Apply Contrapositive equivalence
A conditional statement and its contrapositive are ALWAYS equivalent.
If p → q, then ¬q → ¬p is also true.
These expressions ARE equivalent.

Question 4

Are the following two logical expressions equivalent? Expression 1: ¬(¬p) Expression 2: p Answer Yes or No and explain why.
Step 1: Understand what logical equivalence means
Two expressions are logically equivalent if they have the same truth value for ALL possible combinations of variables.

Step 2: Analyze the expressions
Expression 1: ¬(¬p)
Expression 2: p

Step 3: Apply Double Negation law
Two negations cancel each other out.
¬(¬p) simply gives back p.
These expressions ARE equivalent.

Question 5

Are the following two logical expressions equivalent? Expression 1: p → q Expression 2: ¬q → ¬p Answer Yes or No and explain why.
Step 1: Understand what logical equivalence means
Two expressions are logically equivalent if they have the same truth value for ALL possible combinations of variables.

Step 2: Analyze the expressions
Expression 1: p → q
Expression 2: ¬q → ¬p

Step 3: Apply Contrapositive equivalence
A conditional statement and its contrapositive are ALWAYS equivalent.
If p → q, then ¬q → ¬p is also true.
These expressions ARE equivalent.

Question 6

Are the following two logical expressions equivalent? Expression 1: ¬(¬p) Expression 2: p Answer Yes or No and explain why.
Step 1: Understand what logical equivalence means
Two expressions are logically equivalent if they have the same truth value for ALL possible combinations of variables.

Step 2: Analyze the expressions
Expression 1: ¬(¬p)
Expression 2: p

Step 3: Apply Double Negation law
Two negations cancel each other out.
¬(¬p) simply gives back p.
These expressions ARE equivalent.

Question 7

Are the following two logical expressions equivalent? Expression 1: ¬(p ∧ q) Expression 2: ¬p ∨ ¬q Answer Yes or No and explain why.
Step 1: Understand what logical equivalence means
Two expressions are logically equivalent if they have the same truth value for ALL possible combinations of variables.

Step 2: Analyze the expressions
Expression 1: ¬(p ∧ q)
Expression 2: ¬p ∨ ¬q

Step 3: Apply De Morgan's Law
De Morgan's Law states: ¬(p ∧ q) ≡ ¬p ∨ ¬q
The negation of a conjunction equals the disjunction of negations.
These expressions ARE equivalent.

Verification with truth table:
p=T, q=T: ¬(T∧T)=F and ¬T∨¬T=F ✓
p=T, q=F: ¬(T∧F)=T and ¬T∨¬F=T ✓
p=F, q=T: ¬(F∧T)=T and ¬F∨¬T=T ✓
p=F, q=F: ¬(F∧F)=T and ¬F∨¬F=T ✓

Question 8

Are the following two logical expressions equivalent? Expression 1: ¬(p ∧ q) Expression 2: ¬p ∨ ¬q Answer Yes or No and explain why.
Step 1: Understand what logical equivalence means
Two expressions are logically equivalent if they have the same truth value for ALL possible combinations of variables.

Step 2: Analyze the expressions
Expression 1: ¬(p ∧ q)
Expression 2: ¬p ∨ ¬q

Step 3: Apply De Morgan's Law
De Morgan's Law states: ¬(p ∧ q) ≡ ¬p ∨ ¬q
The negation of a conjunction equals the disjunction of negations.
These expressions ARE equivalent.

Verification with truth table:
p=T, q=T: ¬(T∧T)=F and ¬T∨¬T=F ✓
p=T, q=F: ¬(T∧F)=T and ¬T∨¬F=T ✓
p=F, q=T: ¬(F∧T)=T and ¬F∨¬T=T ✓
p=F, q=F: ¬(F∧F)=T and ¬F∨¬F=T ✓

Question 9

Are the following two logical expressions equivalent? Expression 1: ¬(p ∧ q) Expression 2: ¬p ∧ ¬q Answer Yes or No and explain why.
Step 1: Understand what logical equivalence means
Two expressions are logically equivalent if they have the same truth value for ALL possible combinations of variables.

Step 2: Analyze the expressions
Expression 1: ¬(p ∧ q)
Expression 2: ¬p ∧ ¬q

Step 3: Test with truth table
Testing: ¬(p ∧ q) vs ¬p ∧ ¬q
Counter-example: p=T, q=F
¬(T ∧ F) = ¬F = T
¬T ∧ ¬F = F ∧ T = F
Since they differ, they are NOT equivalent.

Question 10

Are the following two logical expressions equivalent? Expression 1: ¬(p ∧ q) Expression 2: ¬p ∨ ¬q Answer Yes or No and explain why.
Step 1: Understand what logical equivalence means
Two expressions are logically equivalent if they have the same truth value for ALL possible combinations of variables.

Step 2: Analyze the expressions
Expression 1: ¬(p ∧ q)
Expression 2: ¬p ∨ ¬q

Step 3: Apply De Morgan's Law
De Morgan's Law states: ¬(p ∧ q) ≡ ¬p ∨ ¬q
The negation of a conjunction equals the disjunction of negations.
These expressions ARE equivalent.

Verification with truth table:
p=T, q=T: ¬(T∧T)=F and ¬T∨¬T=F ✓
p=T, q=F: ¬(T∧F)=T and ¬T∨¬F=T ✓
p=F, q=T: ¬(F∧T)=T and ¬F∨¬T=T ✓
p=F, q=F: ¬(F∧F)=T and ¬F∨¬F=T ✓

Question 11

Are the following two logical expressions equivalent? Expression 1: p → q Expression 2: q → p Answer Yes or No and explain why.
Step 1: Understand what logical equivalence means
Two expressions are logically equivalent if they have the same truth value for ALL possible combinations of variables.

Step 2: Analyze the expressions
Expression 1: p → q
Expression 2: q → p

Step 3: Test with truth table
p → q (implication) is NOT the same as q → p (converse).
Counter-example: p=F, q=T
p → q = F → T = T
q → p = T → F = F
Since they differ, they are NOT equivalent.

Question 12

Are the following two logical expressions equivalent? Expression 1: ¬(p ∨ q) Expression 2: ¬p ∧ ¬q Answer Yes or No and explain why.
Step 1: Understand what logical equivalence means
Two expressions are logically equivalent if they have the same truth value for ALL possible combinations of variables.

Step 2: Analyze the expressions
Expression 1: ¬(p ∨ q)
Expression 2: ¬p ∧ ¬q

Step 3: Apply De Morgan's Law
De Morgan's Law states: ¬(p ∨ q) ≡ ¬p ∧ ¬q
The negation of a disjunction equals the conjunction of negations.
These expressions ARE equivalent.

Question 13

Are the following two logical expressions equivalent? Expression 1: ¬(p ∧ q) Expression 2: ¬p ∨ ¬q Answer Yes or No and explain why.
Step 1: Understand what logical equivalence means
Two expressions are logically equivalent if they have the same truth value for ALL possible combinations of variables.

Step 2: Analyze the expressions
Expression 1: ¬(p ∧ q)
Expression 2: ¬p ∨ ¬q

Step 3: Apply De Morgan's Law
De Morgan's Law states: ¬(p ∧ q) ≡ ¬p ∨ ¬q
The negation of a conjunction equals the disjunction of negations.
These expressions ARE equivalent.

Verification with truth table:
p=T, q=T: ¬(T∧T)=F and ¬T∨¬T=F ✓
p=T, q=F: ¬(T∧F)=T and ¬T∨¬F=T ✓
p=F, q=T: ¬(F∧T)=T and ¬F∨¬T=T ✓
p=F, q=F: ¬(F∧F)=T and ¬F∨¬F=T ✓

Question 14

Are the following two logical expressions equivalent? Expression 1: p → q Expression 2: ¬q → ¬p Answer Yes or No and explain why.
Step 1: Understand what logical equivalence means
Two expressions are logically equivalent if they have the same truth value for ALL possible combinations of variables.

Step 2: Analyze the expressions
Expression 1: p → q
Expression 2: ¬q → ¬p

Step 3: Apply Contrapositive equivalence
A conditional statement and its contrapositive are ALWAYS equivalent.
If p → q, then ¬q → ¬p is also true.
These expressions ARE equivalent.

Question 15

Are the following two logical expressions equivalent? Expression 1: ¬(¬p) Expression 2: p Answer Yes or No and explain why.
Step 1: Understand what logical equivalence means
Two expressions are logically equivalent if they have the same truth value for ALL possible combinations of variables.

Step 2: Analyze the expressions
Expression 1: ¬(¬p)
Expression 2: p

Step 3: Apply Double Negation law
Two negations cancel each other out.
¬(¬p) simply gives back p.
These expressions ARE equivalent.

Question 16

Are the following two logical expressions equivalent? Expression 1: p → q Expression 2: q → p Answer Yes or No and explain why.
Step 1: Understand what logical equivalence means
Two expressions are logically equivalent if they have the same truth value for ALL possible combinations of variables.

Step 2: Analyze the expressions
Expression 1: p → q
Expression 2: q → p

Step 3: Test with truth table
p → q (implication) is NOT the same as q → p (converse).
Counter-example: p=F, q=T
p → q = F → T = T
q → p = T → F = F
Since they differ, they are NOT equivalent.

Question 17

Are the following two logical expressions equivalent? Expression 1: ¬(p ∨ q) Expression 2: ¬p ∧ ¬q Answer Yes or No and explain why.
Step 1: Understand what logical equivalence means
Two expressions are logically equivalent if they have the same truth value for ALL possible combinations of variables.

Step 2: Analyze the expressions
Expression 1: ¬(p ∨ q)
Expression 2: ¬p ∧ ¬q

Step 3: Apply De Morgan's Law
De Morgan's Law states: ¬(p ∨ q) ≡ ¬p ∧ ¬q
The negation of a disjunction equals the conjunction of negations.
These expressions ARE equivalent.

Question 18

Are the following two logical expressions equivalent? Expression 1: ¬(p ∧ q) Expression 2: ¬p ∧ ¬q Answer Yes or No and explain why.
Step 1: Understand what logical equivalence means
Two expressions are logically equivalent if they have the same truth value for ALL possible combinations of variables.

Step 2: Analyze the expressions
Expression 1: ¬(p ∧ q)
Expression 2: ¬p ∧ ¬q

Step 3: Test with truth table
Testing: ¬(p ∧ q) vs ¬p ∧ ¬q
Counter-example: p=T, q=F
¬(T ∧ F) = ¬F = T
¬T ∧ ¬F = F ∧ T = F
Since they differ, they are NOT equivalent.

Question 19

Are the following two logical expressions equivalent? Expression 1: ¬(p ∧ q) Expression 2: ¬p ∧ ¬q Answer Yes or No and explain why.
Step 1: Understand what logical equivalence means
Two expressions are logically equivalent if they have the same truth value for ALL possible combinations of variables.

Step 2: Analyze the expressions
Expression 1: ¬(p ∧ q)
Expression 2: ¬p ∧ ¬q

Step 3: Test with truth table
Testing: ¬(p ∧ q) vs ¬p ∧ ¬q
Counter-example: p=T, q=F
¬(T ∧ F) = ¬F = T
¬T ∧ ¬F = F ∧ T = F
Since they differ, they are NOT equivalent.

Question 20

Are the following two logical expressions equivalent? Expression 1: ¬(p ∧ q) Expression 2: ¬p ∧ ¬q Answer Yes or No and explain why.
Step 1: Understand what logical equivalence means
Two expressions are logically equivalent if they have the same truth value for ALL possible combinations of variables.

Step 2: Analyze the expressions
Expression 1: ¬(p ∧ q)
Expression 2: ¬p ∧ ¬q

Step 3: Test with truth table
Testing: ¬(p ∧ q) vs ¬p ∧ ¬q
Counter-example: p=T, q=F
¬(T ∧ F) = ¬F = T
¬T ∧ ¬F = F ∧ T = F
Since they differ, they are NOT equivalent.
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