Logical reasoning PrepTest 145 · Section 2 · Question 23

Incorrect. There's no discussion of the mines of other companies, or a discussion of what percent of Velyena mines are operated by Moradco, so there's no way to make this inference.

Incorrect. There's no way of figuring out the relative size of these groups, so this is incorrect.

Incorrect. There's no way to compare gold mines in Velyena vs. those outside of it, so this answer is out of scope.

Correct. Argument or Facts:
Facts

Question Type:
Must Be True

Stimulus Summary:
Mine operated by Moradco in Velyena-most-Never violated an environmental regulation
Gold mine operated by Moradco → Violated an environmental regulation

Answer Anticipation:
We've got a conditional and a most statement, and they share a term, so there's at least a chance we can combine them to make an inference (considering this is a Must be True question, more than a chance!).

However, looking at the shared term, it's negated in the most statement but not in the conditional, so we need to take the contrapositive of that conditional:

not Violated an environmental reg → not Moradco gold mine
Moradco mine in Velnyena-most-not Violated an environmental reg

Now, to determine if the shared term is in the correct positions to make an inference and, since its a conditional/most combo, to determine if the inference is a some or most statement.

For the first question, this is a situation where we can make an inference. We know that most of the Moradco mines in Velnyena haven't violated an environmental regulation, which the conditional guarantees means that it's not a gold mine. So at the very least, we can say that some of the Moradco mines in Velnyena aren't gold mines.

But can we say most? Yes, yes we can. If there are 100 Moradco mines in Velnyena, at least 51 haven't violated an environmental regulation, and all 51 of those aren't gold mines. Therefore, 51 of 100 aren't gold mines—most:

Moradco mine in Velnyena-most-not Moradco gold mine

Answer Explanation:
If you know how to combine conditional and quantified statements, this answer is 100% predictable. If not, it'll probably take a bit of work if you manage to answer it.

Key Takeaway:
Making inferences from conditional statements and quantified statements is a skill where you can memorize the rules and apply them correctly every time with a bit of practice. So practice! Otherwise, you could drive yourself crazy trying to prove the incorrect answers here.

Incorrect. We can tell this is true in Velyena, but not throughout the world.