Logical reasoning PrepTest 119 · Section 3 · Question 25

Incorrect. A plant that receives more rain will tend to be taller, but that doesn't mean it's the only factor in the plant's height. This answer reverses the relationship in the last statement—it's possible that a plant can grow taller than average without double the rainfall if, say, it receives a lot of sunlight.

Incorrect. If the plant has a longer-than-average taproot, then the height is twice as tall as that and it must be above average. However, similar to (A), the stimulus doesn't state that this guarantees it received (or is even likely to have received) over twice the average amount of rain, as there could be many other causes of a false chicory plant growing so tall.

Incorrect. Similar to both (A) and (B), the stimulus establishes receiving that much rain as sufficient to guarantee it grows to an above average height, but there could be other factors that would also result in such growth, so it could be possible for a plant to reach such great heights without receiving so much rain.

Incorrect. The stimulus does establish that more rain tends to result in taller plants, but, again, there could be other factors involved. Additionally, the stimulus notes that this is just a "tendency," so this answer is too strong in assuming that it always means that the two received the "same" amount of rain.

Correct. Argument or Facts:
Facts

Question Type:
Must Be True

Stimulus Summary:
False chicory taproot - _ as long as it is tall
The more rain, the taller the false chicory tends to be
False chicory that receives 2x+ the usual rainfall → Taller than average

Answer Anticipation:
This argument seems like it's going to ask us to do math. Please don't ask us to do math. . .

It's all about false chicory sizes—its height, and the size of its taproot. Those two have a very specific relationship—the plant's taproot is half the size of the height.

This height is governed by rainfall—the more rain, the taller the plant. And, specifically, a plant that receives at least twice the average rainfall is guaranteed to be taller than average.

The third statement is a more specific and stronger version of the second, so let's focus on whether we can use that to say something about the taproot length, inferring from it and the first statement. If a false chicory plant receives at least double the average rainfall, it will be taller than average. And if the length of the taproot is "always" half of its height, then that would also have to be longer than the average taproot. Let's see if that's an answer.

Answer Explanation:
This answer matches our anticipation. The third statement guarantees that a plant receiving more than twice the average amount of rain will reach above-average heights. If the taproot is always half as long as the plant is tall, then that would also guarantee the taproot is longer than average, since the average would be determined by dividing the average height in two.

Key Takeaway:
Don't start doing math on the LSAT, even if it starts throwing numbers at you. The question is going to be about the logic connecting the ideas, not the numbers that are presented.