LSAT Strengthen Questions With Explanations Practice Questions with Answers

LSAT Strengthen Questions With Explanations Practice Questions with Answers

Logic games and reading comprehension often grab the headlines, but your ability to handle LSAT strengthen questions with explanations will largely determine your success in the Logical Reasoning section. These questions account for approximately 15% to 20% of the Logical Reasoning portion of the exam. To excel, you must identify the underlying assumption of an argument and provide a new piece of information that makes the conclusion more likely to be true. Whether you are using a AI Exam Simulator or traditional prep books, mastering this question type is essential for a top-tier score.

Concept Explanation

LSAT strengthen questions require you to select the answer choice that provides the most support for the author's conclusion by bridging the gap between the premises and the final claim. Unlike inference questions, which ask what must be true based on the text, strengthen questions ask you to bring in outside information to bolster the argument. You are looking for a "missing link" or a piece of evidence that eliminates a potential weakness. A successful strategy involves identifying the conclusion, isolating the premises, and spotting the logical flaw or assumption. The correct answer will not necessarily make the conclusion 100% certain, but it will increase the probability of the conclusion being valid compared to the other options. For those looking to refine their approach, utilizing LSAT Prep resources can help categorize these assumptions into common patterns like causal relationships, surveys, and analogies.

Solved Examples

1. Argument: A recent study showed that children who play chess score higher on standardized math tests than those who do not. Therefore, playing chess improves a child's mathematical ability.
   Question: Which of the following, if true, most strengthens the argument?
   1. The study was conducted over a five-year period with a large sample size.
   2. Children in the study were randomly assigned to either a chess-playing group or a control group.
   3. Most math teachers agree that logic is a key component of both chess and mathematics.
   Solution: Choice 2 is the correct answer. The original argument assumes a causal relationship (chess causes better math scores) based on a correlation. Choice 2 eliminates the possibility of "self-selection bias" (i.e., that kids already good at math are the ones who choose to play chess) by using random assignment, thereby strengthening the causal claim.
2. Argument: The city council plans to reduce traffic congestion by building a new light rail system. Since similar systems in nearby cities have reduced car usage by 20%, our city will see a similar reduction.
   Question: Which of the following most strengthens the argument?
   1. The nearby cities have a similar population density and layout to this city.
   2. The cost of building the light rail is lower than the cost of expanding highways.
   3. Public opinion polls show that 60% of residents support the light rail project.
   Solution: Choice 1 is correct. This is an argument by analogy. For an analogy to hold, the two things being compared must be similar in relevant ways. By stating the cities are similar in density and layout, Choice 1 makes it more likely that the results will be replicated.
3. Argument: Sales of organic kale have doubled in the last year. This proves that consumers are becoming more health-conscious.
   Question: Which of the following most strengthens the argument?
   1. The price of organic kale decreased significantly over the last year.
   2. The total number of grocery stores selling organic kale has not increased in the last year.
   3. A survey shows that people are buying kale because they believe it has medicinal properties.
   Solution: Choice 3 is correct. The argument assumes the reason for the sales increase is health consciousness. Choice 3 provides direct evidence for this motivation. Choice 1 would actually weaken the argument by providing an alternative explanation (lower price).

Practice Questions

1. Paleontologists recently found a large cache of dinosaur bones in a single location, all belonging to the same species. They concluded that this species of dinosaur traveled in herds. Which of the following, if true, most strengthens the conclusion?

2. A new law requires all cyclists to wear helmets. Proponents claim this will reduce the number of head injuries. Critics argue it will discourage people from cycling. Which of the following most strengthens the proponents' claim?

3. The university's new parking garage will solve the campus parking shortage because it adds 500 new spaces. Which of the following most strengthens the argument?

4. Many people believe that drinking coffee causes insomnia. However, a study of 1,000 coffee drinkers found that those who drank coffee in the morning slept just as well as non-coffee drinkers. Therefore, coffee does not cause insomnia. Which of the following most strengthens the argument?

5. A company moved its headquarters from a high-tax state to a low-tax state. The CEO claimed this would increase the company's net profit. Which of the following most strengthens the CEO's claim?

6. Farmers who switched to genetically modified (GM) seeds reported higher yields than those using traditional seeds. This proves that GM seeds are more productive. Which of the following most strengthens this?

7. A novelist's latest book sold more copies in its first week than any of her previous books. The publisher concluded that this book is her most popular work to date. Which of the following most strengthens the publisher's conclusion?

8. Research shows that employees who take short breaks every hour are more productive than those who work four hours straight. Thus, management should mandate hourly breaks to increase total output. Which of the following most strengthens the argument?

Answers & Explanations

1. Answer: The bones show evidence of having been buried simultaneously by a single catastrophic event, rather than accumulating over time.
   Explanation: If the bones accumulated over years, it wouldn't prove they lived together. If they died together at once, it strongly suggests they were a group (herd).
2. Answer: In cities with similar laws, the rate of head injuries among cyclists dropped by 40% without a significant decrease in the number of cyclists.
   Explanation: This provides empirical evidence that the desired outcome occurs without the feared negative side effect.
3. Answer: The number of students and faculty members requiring parking is not expected to increase significantly over the next five years.
   Explanation: This strengthens the argument by ensuring the "solution" won't be immediately negated by an increase in demand.
4. Answer: The study also included coffee drinkers who consume coffee in the afternoon and evening, and they also showed no signs of increased insomnia.
   Explanation: This expands the scope of the study to cover the most likely times coffee would cause sleep issues, making the general conclusion more robust.
5. Answer: The cost of moving and setting up the new headquarters is significantly less than the projected annual tax savings.
   Explanation: To increase net profit, the savings must outweigh the expenses of the move.
6. Answer: The farmers using GM seeds and those using traditional seeds used identical irrigation and fertilization techniques.
   Explanation: This controls for other variables, ensuring that the seed type is the likely cause of the yield difference.
7. Answer: The increase in sales was not due to an unusually large marketing budget or a decrease in the book's price.
   Explanation: By ruling out external factors like price or promotion, it strengthens the idea that the book's popularity (intrinsic demand) drove the sales.
8. Answer: The productivity gain from the breaks is greater than the loss of working time during those breaks.
   Explanation: For total output to increase, the quality/speed of work after a break must compensate for the time spent not working.

Frequently Asked Questions

What is the difference between a Strengthen and a Justify question?

A strengthen question asks for information that makes the conclusion more likely, while a justify (or "Sufficient Assumption") question requires an answer that makes the conclusion 100% logically certain. Strengthen answers can be helpful additions, whereas justify answers must be logically bulletproof.

Can the correct answer to a strengthen question bring in new information?

Yes, strengthen questions explicitly allow and often require new information not mentioned in the stimulus. Your task is to accept the answer choices as true and determine which one best supports the argument's logic.

How do I handle causal strengthen questions?

To strengthen a causal claim, look for answers that eliminate alternative causes, show the cause and effect appearing together, or show that the effect does not occur when the cause is absent. You can also refer to Hard GRE Reading Exam Questions for similar logical structures in other standardized tests.

Do I need to find the "missing link" in every strengthen question?

Most strengthen questions rely on a gap between the premise and conclusion, so finding that gap is the most efficient way to identify the correct answer. The answer will either bridge that gap or defend against a potential attack on that gap.

Are extreme words like "all" or "never" okay in strengthen answers?

Unlike "Must Be True" questions where extreme language is often a red flag, strengthen questions can benefit from strong language. If an answer says "all instances" of a problem are solved by a solution, it strengthens the argument much more than if "some instances" are solved.