LSAT Complete the Argument Questions Practice Questions with Answers

LSAT Complete the Argument Questions Practice Questions with Answers

Logical reasoning sections on the Law School Admission Test often include prompts that end with a blank line, requiring you to select the most logical conclusion. These LSAT Complete the Argument questions test your ability to synthesize information and identify the natural progression of a speaker's logic. Because these questions appear in the LSAT Prep curriculum, understanding how to bridge the gap between premises and a final inference is essential for a high score.

Concept Explanation

LSAT Complete the Argument questions are a specific subtype of Must Be True or Main Point questions where the stimulus ends abruptly, and the test-taker must provide the most supported final thought. You are essentially acting as the author to finish the train of thought based strictly on the provided evidence. These questions are easily identified by a blank line (________) at the end of the stimulus or a prompt asking you to choose the option that "most logically completes the argument."

To solve these effectively, you must distinguish between two primary structures:

• Conclusion-Based: The stimulus provides premises and a transition word (like "therefore" or "hence"), and you must supply the main conclusion.
• Premise-Based: The stimulus provides a set of facts or a comparison, and you must supply the final piece of evidence or a sub-conclusion that rounds out the logic.

Success requires avoiding "new" information that isn't supported by the text. Just like reading comprehension tasks on other graduate exams, you must stay within the boundaries of the passage. If the argument establishes a conditional relationship, the completion will often be the application of that rule to a specific case mentioned in the premises.

Solved Examples

Example 1: The Principle Application
Stimulus: Every student who studies for more than ten hours a week passes the bar exam. Sarah studied for twelve hours every week for the last three months. Therefore, ________.

1. Identify the Logic: This is a simple conditional argument. $$\text{Study } > 10 \rightarrow \text{Pass}$$.
2. Apply the Facts: Sarah studied 12 hours, which is greater than 10.
3. Draw the Conclusion: Sarah will pass the bar exam.
4. Final Answer: Sarah will pass the bar exam.

Example 2: The Contrastive Completion
Stimulus: While modern architects prioritize aesthetic minimalism, historical preservationists argue that ornate details are essential for maintaining a city's cultural identity. Since the city council has recently voted to prioritize cultural identity over modern trends, they will likely ________.

1. Identify the Logic: The council is choosing between two competing values. They chose the one associated with ornate details.
2. Predict the Outcome: The council will support projects with ornate details or reject minimalist ones.
3. Final Answer: Reject minimalist designs in favor of ornate, traditional architecture.

Example 3: The Logical Gap
Stimulus: No mammal that lacks fur can survive in the arctic without external heat sources. The recently discovered "Ice-Whale" has no fur and lives exclusively in the arctic. It follows that the Ice-Whale ________.

1. Identify the Logic: No fur + Arctic \u2192 Need external heat.
2. Connect the Variables: The Ice-Whale fits both initial conditions (no fur, lives in arctic).
3. Deduce: The Ice-Whale must have an external heat source.
4. Final Answer: Must possess or utilize some form of external heat source.

Practice Questions

1. Many nutritionists argue that a high-protein diet is essential for muscle recovery. However, recent studies show that excessive protein intake can strain the kidneys. Since elite athletes require both muscle recovery and optimal kidney function, they should ________.

2. The city's new transit plan aims to reduce traffic congestion by increasing the cost of downtown parking. Yet, historical data shows that whenever parking costs rise, commuters switch to side-street parking rather than public transit. Thus, the new plan will likely ________.

3. All members of the board voted in favor of the merger except for those who own shares in the rival company. Since Mr. Henderson is a board member who voted against the merger, it must be true that ________.

4. A software company found that productivity increased by 20% when employees worked four days a week instead of five. Despite this, the CEO decided to maintain the five-day work week to ensure constant client availability. This suggests that the CEO values ________.

5. If a plant is given too much water, its roots will rot. If its roots rot, the plant cannot absorb nutrients. The hibiscus in the garden has stopped absorbing nutrients. Therefore, it is possible that ________.

6. Most successful novelists write every morning. Mark is a successful novelist who never writes in the morning. This indicates that writing in the morning is ________.

7. Research indicates that children who play musical instruments perform better in mathematics. However, this correlation disappears when researchers control for socioeconomic status. This suggests that the link between music and math is ________.

8. The law requires that all vehicles on the highway have functioning brake lights. The blue sedan currently traveling on the highway has a broken left brake light. Consequently, the driver of the blue sedan is ________.

Answers & Explanations

1. Answer: Balance their protein intake to avoid kidney strain while supporting muscle recovery.
   Explanation: The argument sets up a conflict between two needs. The conclusion must address the necessity of satisfying both requirements mentioned in the final premise.
2. Answer: Fail to reduce traffic congestion.
   Explanation: If commuters just move to side streets instead of using transit, the total number of cars (traffic) does not decrease, undermining the plan's goal.
3. Answer: Mr. Henderson owns shares in the rival company.
   Explanation: The stimulus establishes a conditional: $$\text{Vote Against} \rightarrow \text{Own Shares}$$. Since Mr. Henderson voted against, he must own the shares.
4. Answer: Constant client availability more than a 20% increase in productivity.
   Explanation: The CEO chose one outcome over the other despite the known benefit of the alternative, revealing a hierarchy of priorities.
5. Answer: The hibiscus was given too much water.
   Explanation: While not a certainty (as other things could cause root rot), it is a logical possibility based on the chain of events provided.
6. Answer: Not a strictly necessary condition for being a successful novelist.
   Explanation: Since Mark is a counterexample (successful but doesn't write in the morning), the "most" general rule cannot be a universal requirement.
7. Answer: Likely a result of socioeconomic factors rather than a direct causal relationship between music and math.
   Explanation: When a correlation disappears after controlling for a third variable, that third variable is often the actual cause or a common factor.
8. Answer: In violation of the law.
   Explanation: The law requires all brake lights to function. A single broken light means the condition of the law is not met.

Frequently Asked Questions

What is the difference between a Must Be True question and a Complete the Argument question?

While both require you to find a logically supported statement, Complete the Argument questions specifically focus on finishing the author's flow of thought. They often act as the conclusion of the stimulus rather than just any valid inference derived from it.

How can I identify the "blank" in these LSAT questions?

The blank is typically preceded by a transition word like "therefore," "so," or "it follows that," signaling a conclusion. If there is no transition word, the blank usually requires a piece of evidence that logically connects the preceding statements.

Should I bring in outside knowledge for these questions?

No, you should never use outside information to complete an LSAT argument. The correct answer must be supported entirely by the premises provided in the stimulus, even if the premises seem factually questionable in the real world.

Are these questions common in the Logical Reasoning section?

Yes, they appear regularly, usually once or twice per section. They are considered a staple of the LSAT because they test the fundamental ability to follow a logical chain to its end.

What is the most common trap in Complete the Argument questions?

The most common trap is an answer choice that is "too strong" or goes beyond what the premises can prove. Always look for the most conservative conclusion that is strictly supported by the text provided.

Can I use the AI Question Generator for these?

Yes, using an AI Question Generator is a great way to practice these specific types of logical inferences. It allows you to generate various scenarios and practice identifying the missing conclusion across different topics.