[blackhole]

"If all Poggles are Quibbles, then Rizzles exist." Assuming that the above statement is true, which of the following statements must also be true?
   a. If Rizzles exist, then all Poggles are Quibbles.
   b. If Rizzles do not exist, then no Poggles are Quibbles.
   c. If some Poggles are not Quibbles, then Rizzles do not exist.
   d. If Rizzles do not exist, then at least one Poggle is not a Quibble.
   e. If all Quibbles are Poggles, then Rizzles exist.

 

(the correct answer is d)

[redsniper]

I don't see why it can't be c.

[Maniax]

Because there's no part of the statement that says the only way riggles exist is if all poggles are quibbles.

[Colonol Dekker]

I don't see why it can't be B either. And isn't this question focused on comprehension. I don't see a math element to it.

[Hellstryker]

I don't see why it can't be c.

[Spicious]

It's pretty straightforward using first order logic.
(For all x Poggle(x) => Qubble(x)) => there exists y such that Rizzle(y).
The only statement that can be proven from that is D.

C isn't true since implication operates one way.
B isn't true since the negation of all is merely that there exists one that isn't (in this case D).

[Colonol Dekker]

Yeah i follow now. I read the options slower. My brain hurts i'm getting on a train now and sleeping.

[Topgun]

I think they should change the "if" to "If and only if".

[Rian]

But wouldn’t that change the answer?

[Dark RevenantX]

****, I'm going to have to take the math2 subject test this year.  I hope I don't get this (easy to solve) bull****, because I don't want two years of calculus to go wasted.

[CP5670]

That test doesn't cover anything beyond basic trignometry from what I remember.

[BloodEagle]

I think they should change the "if" to "If and only if".

Agreed.

I've always hated how test questions, with regards to every subject, were never absolute.  I also hated how they were never checked for incorrect spelling or grammar usage.

Note: I am speaking about college-grade tests, in case you were wondering.

[Spicious]

I think they should change the "if" to "If and only if".

Agreed.

I've always hated how test questions, with regards to every subject, were never absolute.  I also hated how they were never checked for incorrect spelling or grammar usage.

Note: I am speaking about college-grade tests, in case you were wondering.

Actually, this one is pretty absolute logically. Changing it to if and only if makes A and C valid answers.

[blackhole]

Thankfully, the actual SAT had none of this bullcrap on it.

[Dark RevenantX]

Yeah, the SAT had a different kind of bullcrap that was more annoying than retarded.

[Topgun]

When I took my SAT I bet I could have answered all the math questions correctly if I only had more time.