Logical reasoning PrepTest 102 · Section 4 · Question 26

Incorrect. What we can infer from the stimulus is that they don't move because of food pressure. As such, any other cause of a move is potentially true, so this answer could be true and can be eliminated.

Incorrect. There's nothing in the stimulus that suggests a crow or two might not range a little further for food if it's missing, so this answer could be true. The closest the stimulus gets is saying for most flocks, the hunting range extends up to 80 miles, but that doesn't mean no crow ever flies farther.

Incorrect. Hunting extends as far as 80 miles, so there's no indication that most hunting happens within 5mi of the roost. This answer is trying to get you to mistakenly infer that the 5mi move means that that's where the food is. But they may move when the roost starts to get too run down, and they stick in the area because there's plenty of food!

Incorrect. The stimulus talks about how long flocks of crows normally stay in a roost, but that doesn't speak to how difficult it would be to dislodge them, so it could be extremely difficult!

Correct. Argument or Facts:
Facts

Question Type:
Cannot Be True

Stimulus Summary:
Crows hunt in the 60-80 miles around their roost. When they move roosts, they move ~5 miles away.

Answer Anticipation:
This question is looking for something that can be rejected based on the provided information, so we're looking for something that Cannot Be True. In other words, we need something that's contradicted by the information in the stimulus (or is mostly contradicted, since this is akin to a Most Strongly Supported question in saying "most justifiably" rejected).

Normally, we'd be looking for a conditional statement or a "missing piece" of information supported by a long description of a situation. Here, however, despite the rather long stimulus, it actually boils down to very little information. Crows have roosts, they hunt in a ~70mi radius around it, and they move ~5mi every few years.

The only overlap that really leads to an inference is the overlap in discussing distances. We know that the hunting territory of the crows is much, much larger than the distance they move—~70mi vs. 5mi. If the roost moves 5mi, then the vast majority of the hunting ground at both roosts would overlap. As such, the stimulus strongly suggests that the crows aren't moving to get new hunting ground, or because their current hunting ground is out of food. That would lead to a much further move. Let's find an answer saying that food does play a role in the move, as that would be strongly contradicted by the information in the stimulus.

Answer Explanation:
This answer matches our anticipation. The crows hunt in an up-to 80mi radius around the roost, and they move only 5mi, so it's unlikely that they're moving because they're out of food! Their hunting grounds still largely overlap.

Key Takeaway:
Cannot Be True and Must Be True questions share something in common—they both deal with inferences. For Must Be True questions, the correct answer commonly reflects a potential inference. For Cannot Be True questions, the correct answer commonly rejects a potential inference. In both question types, look for inferences—and inferences are generally derived from multiple statements that have overlapping concepts.