Easy LSAT Strengthen and Weaken Practice Questions Practice Questions

Logical reasoning sections on the Law School Admission Test require you to identify how new information affects the validity of an argument. These Easy LSAT Strengthen and Weaken Practice Questions focus on the fundamental relationship between premises and conclusions, helping you build the intuition needed for higher-level analysis. According to the Law School Admission Council, logical reasoning accounts for approximately half of your scored content, making these question types essential for success.

Concept Explanation

Strengthen and weaken questions ask you to select the piece of information that either bolsters the link between a premise and a conclusion or exposes a gap in that logic. In a strengthen question, your goal is to find an answer choice that makes the conclusion more likely to be true, often by ruling out an alternative explanation or confirming an underlying assumption. Conversely, a weaken question requires you to find information that makes the conclusion less likely to be true, typically by introducing a counterexample or showing that the premises do not necessarily lead to the stated outcome. Both types require you to accept the answer choices as true—even if they introduce outside information—and evaluate their impact on the specific argument provided in the stimulus. Understanding these core mechanics is a vital part of LSAT Prep and serves as the foundation for more complex logical games and reading comprehension tasks.

Solved Examples

1. Strengthen Example:

   Argument: A recent study showed that people who eat breakfast every morning are less likely to be overweight than those who skip it. Therefore, eating breakfast causes people to maintain a healthy weight.

   Step-by-Step Solution:

   1. Identify the conclusion: Eating breakfast causes healthy weight.
   2. Identify the premise: There is a correlation between breakfast and weight.
   3. Find the gap: The argument assumes correlation equals causation.
   4. Strengthen: A good answer would rule out the reverse (e.g., "People who are already at a healthy weight do not have different metabolic rates that make them crave breakfast").

2. Weaken Example:

   Argument: The city's new bike lanes have caused a decrease in car traffic. Since the lanes were installed, the number of cars on Main Street has dropped by 20%.

   Step-by-Step Solution:

   1. Identify the conclusion: Bike lanes caused the traffic decrease.
   2. Identify the premise: Car numbers dropped after lanes were installed.
   3. Find the gap: Something else could have caused the drop.
   4. Weaken: An answer like "A major bridge connecting to Main Street was closed for repairs during the same period" weakens the link by providing an alternative cause.

3. Strengthen Example:

   Argument: The rare Blue-Spotted Frog is dying out because of a new fungus. To save the species, we must move the remaining frogs to a laboratory environment.

   Step-by-Step Solution:

   1. Identify the goal: Move frogs to a lab to save them.
   2. Identify the threat: A fungus.
   3. Strengthen: We need to know the lab is safe. An answer like "The fungus cannot survive in the controlled climate of a laboratory" makes the plan much more likely to succeed.

Practice Questions

1. Argument: Every time the local basketball team wears their red jerseys, they win. Therefore, the red jerseys must be lucky and contribute to their winning streak.

Which of the following, if true, most weakens the argument?

2. Argument: A new vitamin supplement, Vit-Max, was given to a group of students before an exam. The students scored higher than the school average. Thus, Vit-Max improves cognitive performance.

Which of the following, if true, most strengthens the argument?

3. Argument: The price of organic produce has dropped significantly this year. Consequently, more families will likely start buying organic food instead of conventional food.

Which of the following, if true, most weakens the argument?

4. Argument: Company X recently switched to a four-day work week. Since the switch, employee productivity has increased by 15%. Therefore, shorter work weeks lead to higher productivity.

Which of the following, if true, most strengthens the argument?

5. Argument: The mayor claims that the new park will improve public health. However, the park is located in a remote area that is difficult to reach without a car.

Which of the following, if true, most weakens the mayor's claim?

6. Argument: Scientists found that plants grew faster when played classical music. They concluded that the vibrations from the music stimulate plant growth.

Which of the following, if true, most weakens the scientists' conclusion?

7. Argument: To reduce carbon emissions, the government should subsidize electric vehicles (EVs). A recent survey shows that 70% of citizens would buy an EV if it were cheaper.

Which of the following, if true, most strengthens the argument?

8. Argument: The new smartphone model has a battery that lasts twice as long as the previous model. This will surely make it the best-selling phone of the year.

Which of the following, if true, most weakens the argument?

Answers & Explanations

1. Answer: The team only wears red jerseys when playing against the weakest opponents in the league.
   Explanation: This weakens the argument by providing an alternative cause for the wins (weak opponents) rather than the "luck" of the jerseys.
2. Answer: The students in the group were selected randomly from various academic backgrounds and skill levels.
   Explanation: This strengthens the argument by showing that the high scores weren't just due to the students already being high achievers, making it more likely the Vit-Max was the cause.
3. Answer: The price of conventional produce has dropped even more than the price of organic produce.
   Explanation: If conventional food is even cheaper than before, the relative incentive to switch to organic is diminished, weakening the prediction that families will switch.
4. Answer: No other changes, such as new technology or management shifts, were implemented during the same period.
   Explanation: This strengthens the argument by eliminating potential confounding variables, isolating the four-day week as the likely cause of productivity gains. You can use the AI Question Generator to practice identifying these types of causal flaws.
5. Answer: Most residents in the city do not own cars and rely entirely on public transportation that does not serve the park's location.
   Explanation: This weakens the mayor's claim because if the target population cannot reach the park, the park cannot improve their health.
6. Answer: The researchers who played the music also watered those plants more frequently than the control group.
   Explanation: This introduces an alternative explanation (extra water) for the growth, thereby weakening the claim that music vibrations were the cause.
7. Answer: The current high cost of electric vehicles is the primary reason why citizens have not yet purchased them.
   Explanation: This strengthens the link between the subsidy (making them cheaper) and the desired outcome (reducing emissions through increased EV use).
8. Answer: The new smartphone is significantly more expensive than any other phone on the market, and consumers are currently prioritizing price over battery life.
   Explanation: This weakens the conclusion by showing that despite the battery improvement, another factor (price) will likely prevent it from becoming the best-seller.

Frequently Asked Questions

What is the difference between a strengthen question and an assumption question?

A strengthen question asks for any information that helps the argument, whereas an assumption question asks for a specific piece of information that the argument needs to be true to function. While all necessary assumptions strengthen an argument, not all strengtheners are necessary assumptions.

Can I use outside information in LSAT strengthen and weaken questions?

Yes, you must use the outside information provided in the answer choices to evaluate the argument. Unlike "Must Be True" questions, strengthen and weaken questions expect you to bring in new facts to see how they impact the existing logic.

How do I identify the conclusion in a logical reasoning stimulus?

Look for indicator words like "therefore," "thus," "so," or "consequently," or identify the statement that the other sentences are trying to support. The conclusion is the main point or the "final word" of the speaker's argument.

What makes an answer choice "neutral"?

An answer is neutral if it does not affect the probability of the conclusion being true. For example, in an argument about health, a statement about the color of the hospital walls is usually irrelevant and neither strengthens nor weakens the logic.

Should I look for the "perfect" answer?

No, you should look for the best answer among the five choices provided. Sometimes the correct strengthener only helps a little bit, but as long as it helps more than the others, it is the right choice.

How can I improve my speed on these questions?

Practice identifying the core "gap" between the premise and conclusion before looking at the answers. Using tools like the AI Exam Simulator can help you get used to the timing and pressure of the actual test.