And Statements (Conjunction) Examples in Math

Start with the recap, study the fully worked examples, then use the practice problems to check your understanding of And Statements (Conjunction).

This page combines explanation, solved examples, and follow-up practice so you can move from recognition to confident problem-solving in Math.

Concept Recap

A conjunction P∧Q is a compound statement that is true if and only if both constituent statements P and Q are individually true.

To enter a theme park ride, you must be tall enough AND have a valid ticket—both conditions must hold. If you are tall enough but lost your ticket, you cannot ride. A conjunction P∧Q works the same way: it is true only when every single part is true, and false the moment any part fails.

Read the full concept explanation →

How to Use These Examples

  • Read the first worked example with the solution open so the structure is clear.
  • Try the practice problems before revealing each solution.
  • Use the related concepts and background knowledge badges if you feel stuck.

What to Focus On

Core idea: A conjunction P and Q is true exactly when both P and Q are true.

Common stuck point: The procedure for conjunction is the easy part; the trap is declaring P∧Q true when only one part is true. Asking "Does the whole claim require every part to be true at the same time?" first is what keeps a correct-looking calculation from being attached to the wrong concept.

Sense of Study hint: Ask: Does the whole claim require every part to be true at the same time?

Worked Examples

Example 1

easy
Let p: '4 is even' and q: '4<10'. Evaluate p∧q, p∧¬q, and ¬p∧q.

Answer

p∧q=T,p∧¬q=F,¬p∧q=F

First step

1
p is true (4 is even). q is true (4 < 10). So ¬q is false and ¬p is false.

Full solution

  1. 2
    p∧q=T∧T=T.
  2. 3
    p∧¬q=T∧F=F.
  3. 4
    ¬p∧q=F∧T=F.
A conjunction p∧q is true only when both components are true. If either component is false, the conjunction is false.

Example 2

medium
Construct the full truth table for p∧q and use it to show that conjunction is commutative: p∧q≡q∧p.

Example 3

medium
Use De Morgan's law to write ¬(P∧Q) in terms of ¬P and ¬Q.

Example 4

medium
Show the associative law: (P∧Q)∧R≡P∧(Q∧R).

Example 5

medium
Negate the statement: 'Bob is tall AND Bob is fast.'

Example 6

hard
Build a truth table for (P∧Q)∧¬P and identify it.

Example 7

medium
Show P∧P≡P (idempotence).

Example 8

hard
Determine if '(P∨Q) ∧ (P∨¬Q)' simplifies to P.

Example 9

challenge
Find all integers n with 1≤n≤100 satisfying 'n is divisible by 3 AND n is divisible by 5'.

Practice Problems

Try these problems on your own first, then open the solution to compare your method.

Example 1

easy
Determine the truth value of: (a) '3>2 and 3<5', (b) '3>2 and 3>5'.

Example 2

medium
Simplify: find all x∈R satisfying 'x>1 and x<4', and express as an interval.

Example 3

easy
If P is true and Q is true, what is P∧Q?

Example 4

easy
If P is true and Q is false, what is P∧Q?

Example 5

easy
If both P and Q are false, what is P∧Q?

Example 6

easy
Evaluate: '3>2 AND 5>4'.

Example 7

easy
Evaluate: '2 is even AND 2 is prime'.

Example 8

easy
In everyday speech 'tall enough AND has a ticket', can you ride with only a ticket?

Example 9

easy
How many of the 4 truth-table rows make P∧Q true?

Example 10

easy
Evaluate: '7 is even AND 7 is odd'.

Example 11

medium
For what x is 'x>0 AND x<5' true? Express as an interval.

Example 12

medium
Solve: 'x is a multiple of 2 AND a multiple of 3', for positive integers. Describe the solutions.

Example 13

medium
If P∧Q is true, what can you conclude about P and about Q individually?

Example 14

medium
Is P∧Q logically equivalent to Q∧P?

Example 15

medium
Translate to logic and evaluate: '16=4 and 0 is positive'.

Example 16

medium
For 'x2=4 AND x>0', find all real x.

Example 17

medium
Build the truth table column for P∧¬Q.

Example 18

medium
Evaluate 'P∧Q' where P: '10 is divisible by 5' and Q: '10 is divisible by 4'.

Example 19

medium
If P∧Q is false and P is true, what is Q?

Example 20

challenge
How many of the 23=8 rows make P∧Q∧R true, and why?

Example 21

challenge
Show 'P∧(Q∨R)' equals '(P∧Q)∨(P∧R)' (distributivity).

Example 22

challenge
In a survey, a response counts only if 'consented AND completed AND age ≥18'. Of 100 forms, 90 consented, 85 completed, 80 are adults. What is the minimum number of valid responses?

Example 23

easy
How many rows of the truth table for P∧Q are TRUE?

Example 24

easy
Evaluate: '5 is odd AND 5 is prime'.

Example 25

easy
Evaluate: '4 is even AND 4 is prime'.

Example 26

medium
Find all x∈Z with 'x>−2 AND x≤3'.

Example 27

medium
Express the solution to 'x≥0 AND x≤5' as an interval.

Example 28

medium
Determine the truth value of: '2 is irrational AND 2+2=4'.

Example 29

medium
True or false: P∧(P∨Q)≡P.

Example 30

easy
Translate to symbols: 'It is raining AND it is cold.' Let R = raining, C = cold.

Example 31

medium
How many integers n satisfy '1≤n≤10 AND n is prime'?

Example 32

medium
True or false: P∧¬P is always false.

Example 33

medium
Solve: 'x2=9 AND x>0'.

Example 34

medium
Solve over R: 'x>0 AND sin⁡x=0 AND x<2π'.

Example 35

medium
If P is true and ¬Q is true, what is P∧Q?

Example 36

medium
Translate the inequality 1≤x≤5 as a conjunction.

Example 37

hard
How many of the 23=8 rows of the truth table for P∧Q∧R are true?

Background Knowledge

These ideas may be useful before you work through the harder examples.

logical statement