Conditional logic - "only"

[brandonhsi]

I am having a hard time to translate the following statements (1. and 2.) with a word "only" into "A guarantee B" (A --> B). I found myself taking too long to decipher 1. and 2. I could decipher 3. quickly because I do it mechanically (as long as I see "only if" then it follows a necessary condition), which might not be a good thing?

1. The only people who water ski are those who can swim.

2. Only the good dies young.

3. Any statement with "only if"

Could someone help me with a good/common sense way to decipher them, so I can decipher them quickly in the exam?

Thanks!

[tommywallach]

Hey Brandon,

I would just practice (using, for example, our LSAT Arcade) until all of these comes as naturally as the third one does. As for deciphering...that's a tough word to use. Because, technically, they are already written in standard, simple English.

1. The only people who water ski are those who can swim.

So...we know that if somebody water skis, they must swim, because nobody else waterskis. In notation:

WS --> S

2. Only the good die young.

This is the same as the one above, but it's been switched around. You could rewrite it as: The only people who die young are the good.

In notation: DY --> G

3. Steve will come to the party only if Samantha comes.

Logically, if Steve is at the party, we know Samantha must be there, because we were told that Steve's being there required Samantha's being there.

In notation: St --> Sa

I can't tell if I helped or not, because I'm not really doing much in the way of translation...but let me know if that cleared things up!

-t