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Need help with TOUGH conditional statement
Posted: Wed Jul 21, 2010 5:36 pm
by youknowryan
How do I symbolize:
No tax reduction package that would greatly inconvenience parents will be adopted this year.
Is it:
Rule: Tax Reduction Package Adopted - > ~Greatly Inconvenience Parents
Contra: Greatly Inconvenience Parents - > ~Tax Reduction Package Adopted
OR
Rule: ~Greatly Inconvenience Parents - > Tax Reduction Package Adopted
Contra: ~Tax Reduction Package Adopted - > Greatly Inconvenience Parents
I think it is the former, but any clarification would be appreciated. Please explain your rationale.
Re: Need help with TOUGH conditional statement
Posted: Wed Jul 21, 2010 5:43 pm
by KaplanLSATInstructor
The former is more accurate. Consider what the sentence is saying in other words:
This year, we're not going to adopt any package that would greatly inconvenience parents. So, if it greatly inconveniences parents, it will not be adopted this year:
inconv --> no adopt
adopt --> won't inconv.
Sometimes, rewording the sentence helps clarify the logic. And remember: No X are Y translates to X --> Not Y. (For example, "No dogs have wings" translates to "dog --> no wings")
HTH
- Chris
Re: Need help with TOUGH conditional statement
Posted: Wed Jul 21, 2010 5:46 pm
by youknowryan
KaplanLSATInstructor wrote:
inconv --> no adopt
adopt --> won't inconv.
I see that you changed the order from what I had: is the top one the rule and the bottom the contrapositive?
Re: Need help with TOUGH conditional statement
Posted: Wed Jul 21, 2010 6:08 pm
by KaplanLSATInstructor
It doesn't matter -- both statements say the exact same thing, just in different ways. My original rule is just the contrapositive of your original rule and your original rule is just the contrapositive of mine.
There's no definitive "original" and "contrapositive." A contrapositive is merely a way of writing a logically equivalent version of whatever you wrote in the first place. As long as what you write is accurate, the logic will be exactly the same in both statements.
Re: Need help with TOUGH conditional statement
Posted: Wed Jul 21, 2010 6:12 pm
by dakatz
There is no "original". Each conditional statement can be written two ways. "Contrapositive" simply means that you are negating the necessary condition of whichever way you chose to write the statement REGARDLESS of which one you decide to write first. I believe they say this in a Powerscore book, but would you look at a penny and think one side is more valuable than the other? They are the exact same thing written in two different ways.
Re: Need help with TOUGH conditional statement
Posted: Wed Jul 21, 2010 6:54 pm
by quasi-stellar
youknowryan wrote:
No tax reduction package that would greatly inconvenience parents will be adopted this year.
The way i see it (not necessarily correct) is like this:
Greatly inconveniencing parents -> package will not be adopted.
The question of convenience seems sufficient to determine the course of action.
so if adopted, the package is not inconvenient to the parents, which is basically cp of what i wrote above.
Feel free to comment if my reasoning is flawed

On a side note, I am not even sure this is a conditional statement in the first place. But its ok.
Re: Need help with TOUGH conditional statement
Posted: Wed Jul 21, 2010 6:58 pm
by TheLuckyOne
youknowryan wrote:How do I symbolize:
No tax reduction package that would greatly inconvenience parents will be adopted this year.
Is it:
Rule: Tax Reduction Package Adopted - > ~Greatly Inconvenience Parents
Contra: Greatly Inconvenience Parents - > ~Tax Reduction Package Adopted
OR
Rule: ~Greatly Inconvenience Parents - > Tax Reduction Package Adopted
Contra: ~Tax Reduction Package Adopted - > Greatly Inconvenience Parents
I think it is the former, but any clarification would be appreciated. Please explain your rationale.
An easy way to do it is to rephrase a sentence by moving negation into the other clause:
Any tax reduction package that would greatly inconvenience parents will
not be adopted this year. In other words, if inconvenient, then won't be adopted.
Inconvenient --> -Adopted
Re: Need help with TOUGH conditional statement
Posted: Wed Jul 21, 2010 7:59 pm
by youknowryan
KaplanLSATInstructor wrote:It doesn't matter -- both statements say the exact same thing, just in different ways. My original rule is just the contrapositive of your original rule and your original rule is just the contrapositive of mine.
There's no definitive "original" and "contrapositive." A contrapositive is merely a way of writing a logically equivalent version of whatever you wrote in the first place. As long as what you write is accurate, the logic will be exactly the same in both statements.
I'm with you here: I've been reading the LGB and am obsessed with the rule/contrapositive model they proffer. Thanks for the input.
Re: Need help with TOUGH conditional statement
Posted: Wed Jul 21, 2010 9:36 pm
by TrojanHopeful
For a statement that starts with "No": The part that immediately follows "no" is the sufficient condition; if you negate the rest of the statement then you get the necessary condition.
Sufficient = tax reduction package that would greatly inconvenience parents
Necessary = will not be adopted this year.
inconvenience parents > will not be adopted
will be adopted > does not inconvenience parents
Re: Need help with TOUGH conditional statement
Posted: Thu Jul 22, 2010 12:57 am
by quasi-stellar
TrojanHopeful wrote:For a statement that starts with "No": The part that immediately follows "no" is the sufficient condition; if you negate the rest of the statement then you get the necessary condition.
Sufficient = tax reduction package that would greatly inconvenience parents
Necessary = will not be adopted this year.
inconvenience parents > will not be adopted
will be adopted > does not inconvenience parents
Worrrrd. This pretty much sums it up
