Logical reasoning PrepTest 145 · Section 2 · Question 25

Incorrect. The stimulus allows us to infer that elephant seals can dive deeper than Weddell seals. If dolphins can also dive deeper than Weddell seals, there's no way to tell which of the two—dolphins or elephant seals—can dive deeper, so this could be true. Eliminate it.

Incorrect. The first half of this answer lets us infer that Weddel seals can dive deeper than northern fur seals. We already know dolphins can dive deeper than them, as well. Since they both can dive deeper than northern fur seals, it's possible that either can dive deeper than the other, so this answer could be true. Another elimination.

Incorrect. Since Weddell seals are in one of the pairings, and dolphins and northern fur seals in the other, there's no baseline inference that would prevent this from being true unless the Weddell seals reversed the relationship between dolphins and northern fur seals. However, since this answer states that the Weddell seals dive deeper and stay under longer than both, that's not possible, so this could be true. Eliminate this answer, too!

Correct. Argument or Facts:
Facts

Question Type:
Cannot Be True

Stimulus Summary:
Sm/Md marine mammals Ð The longer they can stay underwater, the deeper they can go
Dolphins vs. Northern fur seals Ð Dolphins can dive deeper
Elephant seals vs. Weddell seals Ð Elephant seals can stay under longer

Answer Anticipation:
This stimulus establishes a general rule/relationship and then provides a couple of specific comparisons that can be used with that rule, so let's dive in (yes, pun intended).

First, the dolphins and Northern fur seals. If the dolphins can dive deeper, the rule tells us that they can stay underwater longer.

Second, the two types of seals. If the Elephant seals can stay under longer, they can dive deeper.

It's important to note that we can't draw an inference between these groups, as they don't share any members. As such, we can't determine if any answer that compares an element of one of the pairs to an element from the other is true, and thus it isn't a correct answer. Instead, we're looking for something that can't be true—something that contradicts the information. The correct answer, therefore, will almost certainly state that the dolphins can't stay underwater longer than northern fur seals, or the elephant seals can't dive deeper than the Weddell seals.

. . . And then we get to the answers. And we see that they're providing two comparisons each that will allow us to make cross-group comparisons, and we'll have to juggle this with the information provided in the stimulus. This question is rough for the last one in a section, but there's nothing to do but forge ahead.

Answer Explanation:
An answer that brings in all of the animals! The first half of this answer establishes that northern fur seals can stay under longer/dive deeper than elephant seals. The premise establishes that dolphins can dive deeper still, and elephant seals can dive deeper/stay under longer than Weddell seals. This lets us "rank" all 4 from top (shallow divers/short time) to bottom—Weddell → Elephant → Northern → Dolphin. The second half of this answer violates this ranking, so this is our answer.

Key Takeaway:
While there's a takeaway here, this question is relatively unique, so we're not sure how widely applicable it is. But here goes—the correct answer here was the only one that brought all 4 animals together. In a Cannot be True question, the more details included in an answer, the more likely it is that one of them has gone wrong.

Incorrect. If northern fur seals can stay under longer than Weddell seals, then they can dive deeper, as well. However, elephant seals can also stay under longer/dive deeper than Weddell seals, so there's no way of knowing between the elephant seals and northern fur seals which can dive deeper/stay under longer, so this answer could be true.