341 Answered Questions for the topic logic


What is the difference (if any) between "not true" and "false"?

A fairly simple question I hope someone can help me with.


Is circular reasoning always a fallacy?

Suppose the following dialogue: >... >"I accept only one notion of land property. Namely, 'I am doing my stuff here, therefore I am here". >"But this means," he responded, "you can break... more


How can we reason about "if P then Q" or "P only if Q" statements in propositional logic?

When you have a propositional sentence of the form ***P* ⊃ *Q*** — which we might read as "if *P*, then *Q*" — how can you tell when it is true, or false, based on the truth-values of *P* and *Q*... more


What is the difference between Fact and Truth?

Is it a fallacy to say that a sane person cannot apply rational thought to the motivations of the insane?

A common argument in today's news is that: 1. Someone commits a heinous crime by shooting a bunch of people. 2. Anyone who commits a heinous crime must be insane. 3. Sane people cannot apply... more


Can an argument be valid even though one of its premises is false?

Is it possible for an argument to be valid by virtue of its logical form, but contain a false premise? In other words, can a premise be false even though the argument itself is logically valid?


Could 'cogito ergo sum' possibly be false?

I've heard it postulated by some people that *"we can't truly know anything"*. While that does seem to apply to the vast majority of things, I can't see how *'cogito ergo sum'* can possibly be... more


How Old Is The Rock?

A certain element has a half life of 4.5 billion years. a. You find a rock containing a mixture of the element and lead. You determine that 35​% of the original element​ remains; the other 65​%... more


Bonus calculation question (real situation need help)

You will earn bonus of $10,000 tied to company's revenue target of $5m. Payout will start at 90% target achievement with a 50% incentive payout, growing linearly with achievement, with the ability... more


Logic puzzle with skirts and blouses

Five girls wearing skirts and blouses in two different colors. Using the information below, you should be able to determine which colors the five had on their clothes. The girls are Anne, Grete,... more


Translate the following sentence into symbolic form and form a truth table for it.

The bear ate honey or fish. If the bear ate fish, then it did not eat honey. Hence, it is not the case that the bear ate honey.


problem solving and logic

Given some numbers and you can use any of these numbers twice.How many 2-digit numbers can be made with the numbers.a) 3 and 4b) 3,4 and 5c) 3,4,5 and 6

ratios and logic

A landscape supplier buys 2 tonnes of fertiliser and fills an equal number of plastic bags (different sizes weighing differently) for resale. How many bags of each size will he have if:a) he fills... more
Logic Other


Use the laws of propositional logic to prove p ↔ (p ∧ r) ≡ ¬p ∨ r.

Use the laws of propositional logic to prove p ↔ (p ∧ r) ≡ ¬p ∨ r

Verify is tautology by using logical equivalence

Verify is tautology by using logical equivalence:((p ∨ q) ∧ (p → r) ∧ (∼ r)) → qby showing what law is using

Eric and Marina each wrote two or three poems everyday. Over a period of time, Eric wrote 43 poems while Marina wrote 61.

 How many days were in this period of time?  18,19,20,21, or 22 days   Thanks so much

If x is divisible by 12, then it is divisible by 8

The statement "If x is divisible by 12, then it is divisible by 8" is false is x equals:   a) 4   b) 20   c) 36   d) 48


The negation of the statement ~q∧(~p∨~r) is:

~q∧(~p∨~r)   Whats ts the negation of this statement? 


What is a set of 7 different numbers that has a median of 93?

Math problem that requires logic and understanding of Algebra. 


Translating sentences into propositional logic

a) Alice is wise, if she is a doctor. b) If Alice spoke to Bob, then Eve overheard her. c) If Alice is wise, then she will be neither poor nor unhappy. d) Exactly two of Alice, Bob and Carol... more


If an argument has a false conclusion it must be invalid.(t or f) ?

If an argument has a false conclusion it must be invalid. 


Proofs, Math logic

How can you prove that one positive integer is less than another? A<B  


Set Theory/Math Logic

Is there any way to prove that   - Every point in A intersect B is greater than or equal to 1?   - The intersection of two sets has a point in commonwith another set?   If there is no way to... more

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