Logical reasoning PrepTest 126 · Section 1 · Question 25

Incorrect. This answer is an inference derived by combining statements #2 and #3.

Incorrect. This answer is an inference derived by combining statements #1 and #2.

Correct. Argument or Facts:
Facts

Question Type:
Bizarro Must Be True

Stimulus Summary:
(1) 20thc art -some- Great art
(2) Great art → Involves original ideas
(3) not Influential art → not Great art

Answer Anticipation:
First, note the question type—Bizarro Must Be True. This is not a Cannot be True question. The difference is this. In a Bizarro Must Be True question, 4 answers must be true and are wrong; one answer could be false and is right. In a Cannot be True question, 4 answers could be true and are wrong; one answer must be false and is right.

With that said, let's get working on these conditional and quantifier statements! First step? Let's take the contrapositive of #3 so that it shares a term with the other statements:
(3) Great art → Influential art

Any hope of chaining those two conditional statements is now out the window, as they share a sufficient condition. When that happens, we can actually combine them in another way:
Great art → Involves original ideas AND Influential art

Normally, we'd split a conditional that has an AND necessary condition to make it easier to work with, but it's just as valid to combine them this way.

After that, it's time to work through the combinations using our quantifier rules. Since each statement shares a term with the others, and since the shared term between the conditionals and the some statement is the sufficient condition of the conditional, we can form inferences from each one. And since there are no most statements (where one combination of a most and conditional statement yields a most inference), all of the inferences will be some statements:
1+2) 20thc art -some- Involves original ideas
1+3) 20thc art -some- Influential art
2+3) Involves original ideas -some- Influential art

If any of these look wrong to you, it's time to review your quantifier rules! Let's head to the answers and eliminate everything that matches with one of these inferences.

Answer Explanation:
This answer is an invalid inference derived by chaining the two conditionals together. However, since they share a sufficient condition, they can't be combined in that manner, so this is the correct answer—it could be false.

Key Takeaway:
On an average LR section, there will be 1-2 questions that require you to use your skills at making inferences using quantified statements. This skill is 100% learnable if you put the time in to learn the concepts and practice them. It's absolutely worth the time and effort to get these points by spending the time to learn these skills.

Incorrect. This answer is a combination of the two conditionals in a valid manner. If great art guarantees that the art involves original ideas, and great art guarantees that the art is influential, then great art guarantees both of those things. Individual conditionals that share a sufficient condition can have their necessary conditions validly combined in this manner.

Incorrect. This can be a tempting answer at first! It appears to be combining our first two inferred statements (1+2 and 1+3), which shouldn't be allowed because they're both some statements, and two some statements can't be combined to form a valid inference. However, statement #1 can be combined with our combined conditional—Great art → Involves original ideas AND Influential art—to get this answer, so it must be true.