Question on a Question Forum

[enveng427]

I'm currently working through the McGraw-Hill Conquering LSAT Logic Games 3rd edition. I'm really new to studying this stuff (read within the past week). I don't plan on taking the LSAT any time real soon (thinking next June). However, this one constraint really confuses me. It says, "Anna gets into the pool only if Chris gets into the pool." Shouldn't that be the same as, "If Chris gets into the pool, Anna gets into the pool."? If so, shouldn't that be mapped C->A not A->C. Please let me know if I'm doing something wrong here.

[ScottRiqui]

I'm currently working through the McGraw-Hill Conquering LSAT Logic Games 3rd edition. I'm really new to studying this stuff (read within the past week). I don't plan on taking the LSAT any time real soon (thinking next June). However, this one constraint really confuses me. It says, "Anna gets into the pool only if Chris gets into the pool." Shouldn't that be the same as, "If Chris gets into the pool, Anna gets into the pool."? If so, shouldn't that be mapped C->A not A->C. Please let me know if I'm doing something wrong here.

No, what the statement is saying is that Anna won't get into the pool unless Chris does. So if Anna is in the pool, you know Chris must be there too, or else she wouldn't have gotten in. This translates to (A -> C).

There's nothing in the statement that says Anna has to be in the pool in order for Chris to get in, so (C -> A) is incorrect.

[enveng427]

Thanks, I guess that makes sense.

[mindarmed]

Don't use McGraw Hill. Purchase Manhattan LSAT.

[altoid99]

If you aren't even able to distinguish between necessary and sufficient conditions I'd suggest purchasing new study materials. McGraw Hill is constantly mocked on here for being one of the worst in the LSAT prep business fwiw

[SecondWind]

Don't use McGraw Hill. Purchase Manhattan LSAT.

^Yeah don't use McGraw Hill. Use the LG Bible or Manhattan.

"Only if" is counter intuitive. One way I remember "only if" is if it's in the middle then the "if" goes to the front. If it's at the front the "if" goes to the middle.

Ex.

Only if form: XXXXX1 only if XXXXX2

Converted to if-then form: If XXXXXX1 then XXXXXX2
____________________________
Ex 2.

Only if form: Only if XXXXX1, XXXXX2

Intermediate step where "If" placed in the middle: XXXXXX1 if XXXXXX2

Rewritten to if-then form: If XXXXX2 then XXXXXX1

Make sense?

[bp shinners]

"Only if" is counter intuitive. One way I remember "only if" is if it's in the middle then the "if" goes to the front. If it's at the front the "if" goes to the middle.

A much easier way is to know that "only if" introduces a necessary condition - it's the same as "only".

[Nova]

Don't use McGraw Hill. Purchase Manhattan LSAT.

[SecondWind]

"Only if" is counter intuitive. One way I remember "only if" is if it's in the middle then the "if" goes to the front. If it's at the front the "if" goes to the middle.

A much easier way is to know that "only if" introduces a necessary condition - it's the same as "only".

I like this way too.

[enveng427]

I don't have the Manhattan books right now. Understand, I'm not being cheap I just have the powerscore bibles in hand. Are they good? The TLS forum "Guides, Advice and Tools" seems to have them on each recommended list. Are these books going to hurt my studying in any way? Or should I use them and then get the Manhattan ones? I do have 8 months. I can do a lot of studying.

[magickware]

Poor study material will hurt you, as the purpose and intent behind the books differ wildly.

For example, the Princeton Review book is absolute trash. The book is designed to teach you stupid tricks and mechanisms that only work for the simplest questions and will leave you absolutely clueless for the difficult ones (basically everything after Q 13 on LR)

Get Manhattan LSAT and/or LSAT Trainer. I personally like the Trainer better now, since it feels like a condensed and distilled version of all three Manhattan LSAT books, teaches you just about everything you need to know, and fundamentally gets at the point that every bloody question besides the inference family question-types are wrong in some way and you need to find what's wrong.

It's so vitally important that you get this. The sooner you understand this, the better.