GRE Inference Questions Practice Questions with Answers

Concept Explanation

GRE Inference Questions are Reading Comprehension tasks that require you to identify a statement that must be true based solely on the information provided in the passage. Unlike detail questions that ask for a literal restatement of facts, inference questions demand that you read between the lines to find a conclusion that is logically supported by the text. To succeed in GRE Prep, you must understand that a valid inference is not a creative guess or a broad generalization; it is a "must-be-true" claim that relies on the evidence given without introducing outside knowledge.

When approaching these questions, look for phrases like "the passage suggests," "it can be inferred," or "the author implies." These are signals that the answer won't be explicitly stated word-for-word. However, the most common mistake students make is choosing an answer that is plausible in the real world but not supported by the specific text provided. In the context of formal logic, an inference is a deduction where the truth of the premises guarantees the truth of the conclusion.

To evaluate options effectively, use the following criteria:

• Direct Support: Can you point to 1-2 sentences that logically lead to this conclusion?

• Avoid Extremes: Be wary of words like "always," "never," "only," or "best" unless the passage uses similarly strong language.

• Stay Within Scope: If the passage discusses the dietary habits of 18th-century sailors, an inference about 18th-century merchants is likely incorrect.

Solved Examples

Example 1: "While most 19th-century novelists focused on the rising middle class, Sarah Orne Jewett's work predominantly featured the declining fishing communities of Maine, capturing a way of life that was rapidly vanishing due to industrialization."

1. Identify the facts: Most novelists wrote about the middle class. Jewett wrote about fishing communities. These communities were declining because of industrialization.

2. Evaluate the Inference: We can infer that Jewett’s subject matter was atypical for her time.

3. Solution: Since the text states "most" novelists focused on a different group (the middle class), Jewett's focus on fishing communities distinguishes her from the majority of her contemporaries.

Example 2: "Recent studies show that plants treated with mycorrhizal fungi exhibit a 30% increase in phosphorus uptake compared to plants grown in sterile soil, even when phosphorus levels in the soil are identical."

1. Identify the facts: Fungi presence leads to more phosphorus uptake. Soil levels are the same in both groups.

2. Evaluate the Inference: Mycorrhizal fungi play a functional role in a plant's ability to absorb nutrients.

3. Solution: Because the soil phosphorus is constant but the uptake varies based on the presence of the fungi, the fungi must be the mechanism facilitating that increased absorption.

Example 3: "The city's new zoning law prohibits the construction of buildings taller than six stories in the historic district. However, the Grand Hotel, located in the heart of the historic district, stands ten stories tall."

1. Identify the facts: New law = max 6 stories. Grand Hotel = 10 stories. Grand Hotel is in the district.

2. Evaluate the Inference: The Grand Hotel was likely built before the current zoning law was enacted.

3. Solution: If the hotel currently exists and exceeds the limit set by the "new" law, it must have been constructed under a different set of regulations or before these specific restrictions existed.

Practice Questions

1. In the late Triassic period, the presence of various species of phytosaurs—crocodile-like reptiles—suggests that freshwater ecosystems were highly productive. However, fossils of these creatures are rarely found in the same strata as early dinosaur remains, which are typically located in more arid, upland environments.

Which of the following can be inferred from the passage?

2. Critics of the new high-speed rail proposal argue that the $12 billion price tag is prohibitive. Yet, the same critics supported a highway expansion project last year that cost $15 billion and served fewer projected commuters than the rail line is expected to carry.

The passage suggests that the critics’ opposition to the rail line is:

3. Standardized test scores in the district rose by 15% following the implementation of a mandatory breakfast program. During the same period, the district also reduced average class sizes from 30 to 22 students.

Based on the passage, which of the following must be true?

4. Many astronomers believe that Europa, a moon of Jupiter, possesses a subsurface ocean of liquid water. This belief is based on the moon's fractured surface ice and magnetic field readings, which are consistent with the presence of a conductive fluid like saltwater.

The passage implies that if Europa did not have a magnetic field, astronomers would:

5. Although the use of synthetic fertilizers has increased crop yields globally, it has also led to significant nitrogen runoff into local waterways. In contrast, organic farming methods utilize compost, which releases nitrogen more slowly and is more easily absorbed by the soil matrix.

It can be inferred from the passage that organic farming is:

6. The 1920s saw a massive influx of rural Americans into urban centers. This demographic shift coincided with the rise of jazz music, which originated in African American communities and gained widespread popularity in cities like New York and Chicago.

The passage suggests which of the following about jazz music in the 1920s?

7. A recent study found that employees who take a 15-minute walk during their lunch break report higher levels of afternoon productivity than those who stay at their desks. Interestingly, this effect was observed regardless of whether the employees walked alone or in groups.

Which of the following is supported by the study?

8. The Rembrandt painting "The Night Watch" is famous for its use of tenebrism, a style emphasizing dramatic contrasts between light and dark. While some contemporaries criticized the painting for its lack of clarity, modern art historians praise it for its emotional depth.

The passage implies that the use of tenebrism:

Answers & Explanations

1. Answer: Early dinosaurs and phytosaurs likely occupied different ecological niches. The passage states phytosaurs were in freshwater ecosystems while dinosaurs were in arid, upland environments. This physical separation in different habitats (niches) is the only direct inference supported.

2. Answer: Not based solely on the financial cost of the project. Since the critics supported a more expensive project ($15 billion) with fewer benefits (fewer commuters) previously, their current objection to a $12 billion project cannot be logically explained by the cost alone.

3. Answer: It is impossible to determine the exact contribution of the breakfast program to the score increase. Because two major changes (breakfast and class size reduction) happened simultaneously, the passage provides no way to isolate the effect of one from the other.

4. Answer: Have less evidence to support the theory of a subsurface ocean. The passage lists the magnetic field as one of the two primary pieces of evidence for the ocean. Removing one piece of evidence naturally weakens the basis for the belief.

5. Answer: Likely to result in less nitrogen runoff than synthetic fertilizer use. If compost releases nitrogen more slowly and is better absorbed by the soil, it follows that less of it would be left to run off into water compared to synthetic versions.

6. Answer: Its growth was contemporaneous with a period of significant internal migration. The text explicitly links the rise of jazz in cities to the "massive influx" of people moving from rural to urban areas.

7. Answer: Social interaction is not the primary driver of the productivity boost seen in walking employees. Since the effect occurred "regardless of whether the employees walked alone or in groups," the social aspect is not the necessary variable for the result.

8. Answer: Was a point of contention among viewers during the artist's lifetime. The passage notes that "contemporaries criticized" the work for its lack of clarity, which was a direct result of the tenebrism style.

1. If a passage states that "most" mammals are viviparous but the platypus lays eggs, what can be inferred?

• AThe platypus is not a mammal
• BThe platypus is an exception to a common mammalian trait
• CViviparity is required for an animal to be a mammal
• DAll egg-laying animals are related to the platypus

Frequently Asked Questions

What is the difference between an inference and a detail question?

A detail question asks you to locate information explicitly stated in the text, whereas an inference question asks for a conclusion that is logically necessitated by the text but not explicitly written. For further practice on data-driven details, you might explore GRE Data Interpretation Questions.

Can I use my own outside knowledge for GRE inference questions?

No, you must strictly use the information provided in the passage to avoid "common sense" traps that are not supported by the text. This is similar to the logic required for GRE Data Sufficiency Questions where you must work only with the given constraints.

How do I identify the "scope" of a passage?

Scope refers to the specific boundaries of the subject matter, such as the time period, geographic location, or specific group being discussed. If you are analyzing trends, you may find that GRE Statistics Practice Questions help sharpen your ability to identify the limits of a dataset.

Are "most likely" answers the same as inferences?

In the GRE context, an inference is something that "must be true" based on the logic of the passage, rather than just a probable guess. For more on logic and likelihood, check out GRE Probability Practice Questions.

What are common "trap" answers in inference questions?

Common traps include "out of scope" answers, "exaggerated" claims using extreme language, and "flipped" relationships where the cause and effect are reversed. You can refine your analytical skills by practicing with the AI Question Generator to see how these traps are constructed.

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