PT 74 lg #23

Prepare for the LSAT or discuss it with others in this forum.
gojj11

Posts: 3
Joined: Tue Dec 02, 2014 5:29 am

PT 74 lg #23

I still cannot get it.

As I know, contrapositive of ''If not K to T -> both A and B to T" is "either A or B is not to T(or Unless either A or B to T) -> K to T".

Why E is wrong?

I'm getting confused now

leslieknope

Posts: 1112
Joined: Sun Apr 15, 2012 8:53 pm

Re: PT 74 lg #23

E says "either H or F to T" and translates to "/(H or M) to T ----> K to T". That's different than the language in the rule, which calls for a block. C says "/K to T---> FM to T", which, since FH are basically the same item due to the block language, makes it correct.

gojj11

Posts: 3
Joined: Tue Dec 02, 2014 5:29 am

Re: PT 74 lg #23

leslieknope wrote:E says "either H or F to T" and translates to "/(H or M) to T ----> K to T". That's different than the language in the rule, which calls for a block. C says "/K to T---> FM to T", which, since FH are basically the same item due to the block language, makes it correct.

thanks! got what I missed. really helped!

Rook

Posts: 20
Joined: Thu Dec 18, 2014 4:52 pm

Re: PT 74 lg #23

can someone explain to me how exactly you go about diagramming C? as far as i understand, whatever comes after the 'unless' is the necessary condition, and whatever comes before it is the sufficient negated. i dont know how to diagram this rule, as unless is the first word.

leslieknope

Posts: 1112
Joined: Sun Apr 15, 2012 8:53 pm

Re: PT 74 lg #23

Rook wrote:can someone explain to me how exactly you go about diagramming C? as far as i understand, whatever comes after the 'unless' is the necessary condition, and whatever comes before it is the sufficient negated. i dont know how to diagram this rule, as unless is the first word.

That's actually the trick to diagram the contrapositive. I personally find it easier to think of unless (and without/except/until) as negate sufficient indicators. You take whatever is after the unless, negate it, and that's your sufficient condition. The other term is the necessary condition. So "Unless K is in T, F and M are in T" becomes "/K to T---> FM to T."

Rook

Posts: 20
Joined: Thu Dec 18, 2014 4:52 pm

Re: PT 74 lg #23

leslieknope wrote:
Rook wrote:can someone explain to me how exactly you go about diagramming C? as far as i understand, whatever comes after the 'unless' is the necessary condition, and whatever comes before it is the sufficient negated. i dont know how to diagram this rule, as unless is the first word.

That's actually the trick to diagram the contrapositive. I personally find it easier to think of unless (and without/except/until) as negate sufficient indicators. You take whatever is after the unless, negate it, and that's your sufficient condition. The other term is the necessary condition. So "Unless K is in T, F and M are in T" becomes "/K to T---> FM to T."

i see...thanks for the explanation!