What is the contrapositive of this statement
Posted: Wed Dec 01, 2010 2:06 pm
A-->B+C
Thanks!!
Thanks!!
not b or not c--->not awanderlust wrote:A-->B+C
Thanks!!
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Re: What is the contrapositive of this statement
Posted: Wed Dec 01, 2010 2:08 pm
Re: What is the contrapositive of this statement
Posted: Wed Dec 01, 2010 2:08 pm
Contrapositive:wanderlust wrote:A-->B+C
Thanks!!
If not BOTH B and C, not A.
Re: What is the contrapositive of this statement
Posted: Wed Dec 01, 2010 2:09 pm
This one.icouldbuyu wrote:not b or not c--->not awanderlust wrote:A-->B+C
Thanks!!
Re: What is the contrapositive of this statement
Posted: Wed Dec 01, 2010 2:20 pm
.
Re: What is the contrapositive of this statement
Posted: Wed Dec 01, 2010 2:29 pm
I think both answers given so far are equivalent, since
~(B AND C) == (~B OR ~C)
~(B AND C) == (~B OR ~C)
Re: What is the contrapositive of this statement
Posted: Wed Dec 01, 2010 2:31 pm
Yep, they are logically equal.
Re: What is the contrapositive of this statement
Posted: Wed Dec 01, 2010 2:40 pm
but ~(B AND C) =/=~B and ~CScottRiqui wrote:I think both answers given so far are equivalent, since
~(B AND C) == (~B OR ~C)
Re: What is the contrapositive of this statement
Posted: Wed Dec 01, 2010 2:49 pm
wanderlust wrote:but ~(B AND C) =/=~B and ~CScottRiqui wrote:I think both answers given so far are equivalent, since
~(B AND C) == (~B OR ~C)
I guess it depends on how you convert musicfor18's text (If not BOTH B and C) into symbols.
I read it as ~(B AND C), rather than (~B AND ~C).
To me, the "BOTH" qualifier means that B and C go together in the parentheses with an AND, and that the NOT notation applies to the entire parenthetical statement.
Re: What is the contrapositive of this statement
Posted: Wed Dec 01, 2010 2:55 pm
Original: A --> B+C
Contrapositive: ~B or ~C --> ~A
If B is absent but C is there, then A is absent. If B is there but C is absent, then A is absent. If both B and C are absent, then A is absent. I wouldn't write ~B and ~C --> ~A because all it takes is for either B or C to be absent to have A be absent.
Contrapositive: ~B or ~C --> ~A
If B is absent but C is there, then A is absent. If B is there but C is absent, then A is absent. If both B and C are absent, then A is absent. I wouldn't write ~B and ~C --> ~A because all it takes is for either B or C to be absent to have A be absent.
Re: What is the contrapositive of this statement
Posted: Wed Dec 01, 2010 3:39 pm
Ignore everything else you've seen up to now and just focus on this, as it is actually correct. Only half of the other people's replies won't fuck you over on test day, lol.SchopenhauerFTW wrote:Original: A --> B+C
Contrapositive: ~B or ~C --> ~A
If B is absent but C is there, then A is absent. If B is there but C is absent, then A is absent. If both B and C are absent, then A is absent. I wouldn't write ~B and ~C --> ~A because all it takes is for either B or C to be absent to have A be absent.
Re: What is the contrapositive of this statement
Posted: Wed Dec 01, 2010 3:53 pm
I'm glad somebody got it correct. LGB and/or conditional statements, look it up.SchopenhauerFTW wrote:Original: A --> B+C
Contrapositive: ~B or ~C --> ~A
If B is absent but C is there, then A is absent. If B is there but C is absent, then A is absent. If both B and C are absent, then A is absent. I wouldn't write ~B and ~C --> ~A because all it takes is for either B or C to be absent to have A be absent.
Re: What is the contrapositive of this statement
Posted: Wed Dec 01, 2010 3:58 pm
musicfor18 wrote:Contrapositive:wanderlust wrote:A-->B+C
Thanks!!
If not BOTH B and C, not A.
No offense, but how did you get a 167?
Re: What is the contrapositive of this statement
Posted: Wed Dec 01, 2010 3:59 pm
DeMorgan's Law FTW!
~(A&B) ::~A v ~B
~(AvB) ::~A & ~B
~(A&B) ::~A v ~B
~(AvB) ::~A & ~B
Re: What is the contrapositive of this statement
Posted: Wed Dec 01, 2010 4:02 pm
Huh? As noted above, he (or she) isn't wrong. It's just worded differently. Not B or not C is the same as "not both."icouldbuyu wrote:musicfor18 wrote:Contrapositive:wanderlust wrote:A-->B+C
Thanks!!
If not BOTH B and C, not A.
No offense, but how did you get a 167?
Re: What is the contrapositive of this statement
Posted: Wed Dec 01, 2010 4:07 pm
As was already pointed out, the answer isn't wrong. The natural way to read 'If not BOTH B and C, not A' is with the negation having wide scope in the antecedent: ~(B & C) --> ~A.icouldbuyu wrote:musicfor18 wrote:Contrapositive:wanderlust wrote:A-->B+C
Thanks!!
If not BOTH B and C, not A.
No offense, but how did you get a 167?
That's the right answer.
Re: What is the contrapositive of this statement
Posted: Wed Dec 01, 2010 5:29 pm
Agreed, but it's still a very trippy way to say it. Most books won't say it this way, because even if people at the 90th percentile will understand it, it's a mindfuck for people under the 90th percentile.tsutsik wrote:As was already pointed out, the answer isn't wrong. The natural way to read 'If not BOTH B and C, not A' is with the negation having wide scope in the antecedent: ~(B & C) --> ~A.icouldbuyu wrote:musicfor18 wrote:Contrapositive:wanderlust wrote:A-->B+C
Thanks!!
If not BOTH B and C, not A.
No offense, but how did you get a 167?
That's the right answer.
Re: What is the contrapositive of this statement
Posted: Wed Dec 01, 2010 8:33 pm
No offense, but how can you be so oblivious?icouldbuyu wrote:musicfor18 wrote:Contrapositive:wanderlust wrote:A-->B+C
Thanks!!
If not BOTH B and C, not A.
No offense, but how did you get a 167?
Re: What is the contrapositive of this statement
Posted: Wed Dec 01, 2010 8:45 pm
My answer, although completely correct, is probably not as well worded as the other. Basically, though, if either B or C is absent, A is absent.
Re: What is the contrapositive of this statement
Posted: Wed Dec 01, 2010 8:59 pm
JazzOne wrote:No offense, but how can you be so oblivious?icouldbuyu wrote:musicfor18 wrote:Contrapositive:wanderlust wrote:A-->B+C
Thanks!!
If not BOTH B and C, not A.
No offense, but how did you get a 167?
Re: What is the contrapositive of this statement
Posted: Thu Dec 02, 2010 1:30 am
I love it when someone says something as condescending as "how did you get a 167" based on information they are mistaken on themselves......there was nothing wrong at all with person's explanation at all, clearly earned their 167
Re: What is the contrapositive of this statement
Posted: Thu Dec 02, 2010 2:12 am
Wow. The first reply was adequate. The rest was pure entertainment. 
Re: What is the contrapositive of this statement
Posted: Thu Dec 02, 2010 2:17 am
Truly amazing that an incredibly simple question which was fully answered in the 1st response needs 22 responses and unnecessary namecalling.
Re: What is the contrapositive of this statement
Posted: Thu Dec 02, 2010 2:22 am
+ One hundred thousand trilliondakatz wrote:Truly amazing that an incredibly simple question which was fully answered in the 1st response needs 22 responses and unnecessary namecalling.
Re: What is the contrapositive of this statement
Posted: Thu Dec 02, 2010 2:28 am
If not B and C ----> A