# [SOLVED] Propositional logic Discrete Mathematics

Tags: discrete, logic, mathematics, propositional, solved
 P: 18 1. The problem statement, all variables and given/known data Assuming atleast one of the following statements is true, which one is it? why? a. Exactly one of these statements is true b. Exactly two of these statements are true c. Exactly three of these statements are true d. Exactly four of these statements are true e. Exactly five of these statements are true 2. Relevant equations These are propositions, which can either be true or false, but not both. Total number of statements = 5 hence n = 5. Atleast one is true so n-1 3. The attempt at a solution Inputting the above equation n-1=4, so exactly four of these statements is true. d points to this statement, which is true.
P: 18
 Quote by fsbadr 1. The problem statement, all variables and given/known data Assuming atleast one of the following statements is true, which one is it? why? a. Exactly one of these statements is true b. Exactly two of these statements are true c. Exactly three of these statements are true d. Exactly four of these statements are true e. Exactly five of these statements are true 2. Relevant equations These are propositions, which can either be true or false, but not both. Total number of statements = 5 hence n = 5. Atleast one is true so n-1 3. The attempt at a solution Inputting the above equation n-1=4, so exactly four of these statements is true. d points to this statement, which is true.
Can someone please verify whether I am right or not? Thanks a lot
 Sci Advisor HW Helper P: 9,398 Why did you introduce n? Anyway, I see absolutely no logic in your argument. Is it possible for two of those statements to be true?
P: 18

## [SOLVED] Propositional logic Discrete Mathematics

 Quote by matt grime Why did you introduce n? Anyway, I see absolutely no logic in your argument. Is it possible for two of those statements to be true?
It is possible for more than one of these statements to be true. I have come up with n because of the number of statements is 5 and assigned n to the number of statements. If you feel this is not right, you could point me in the right direction and I could get started on that.
 Sci Advisor HW Helper P: 9,398 What does assigning n to be the number of statements do? Look, just read the statements and please think again about what I said. Is it possible for two of those statements to be simultaneously true? (This is a BIG hint, so please don't ignore it again.)
P: 18
 Quote by matt grime What does assigning n to be the number of statements do? Look, just read the statements and please think again about what I said. Is it possible for two of those statements to be simultaneously true? (This is a BIG hint, so please don't ignore it again.)
Thank you for the hint. I will surely look into it.
 P: 617 in general try to assume one of the solutions is correct and see if you reach a contradiction
 P: 18 I made up a truth table (I know this is a crude way) but also came up with 4 Truth values. Now, if all the statements are true then the fifth statement which is the conclusion is true also, else it is false. So, a,b,c and d are true?
 Sci Advisor HW Helper Thanks P: 25,008 You ignored matt again. Two of the statements can't be true at the same time. They would contradict each other.
 Sci Advisor HW Helper P: 9,398 For the love of God will you just think for a second! Every pair of statements are contradictory! Look, you've got me using exclamation marks, that's how annoyed I am: imagine I'm smacking my head against the desk. That's what you've driven me to. You honestly don't see that two things like: a) exactly X of these statements are true b) exactly Y of these statements are true are mutually incompatible if X doesn't equal Y?
 P: 18 Matt, Thanks. This is my first class at discrete math. I just got this assignment yesterday and am also attempting to solve this myself. Call me slow, but I guess everything comes to everyone at a different pace. You cant blame me for trying and I while I may be trying wrong, atleast I try. Eventually I will come up with the right answer. Thanks again for your help.
 Sci Advisor HW Helper P: 9,398 This has nothing to do with "discrete maths". Let me put it this way: I have 5 marbles. I tell you that exactly 4 of them are red. Then I tell you that exactly 3 of them are red. Can I have been telling you the truth both times? Of course not. I cannot tell you two contradictory statements about the same thing and have them both be true.

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