LSAT Logical Reasoning: Weaken the Argument Questions

Question 1

A city council member argues that building a new highway through the suburbs will reduce downtown traffic congestion because commuters will have a faster route into the city.
Which of the following, if true, most weakens this argument?

Accepted Answer

Studies show that new roads attract additional drivers, increasing total traffic volume.

Answer

The highway construction will take three years to complete.

Answer

Some commuters prefer public transportation over driving.

Answer

The highway will pass through areas with low population density.

Answer

Downtown parking fees have increased significantly in recent years.

Question 2

A nutritionist claims that people who eat breakfast daily perform better at work than those who skip breakfast, citing a study of office workers. Which of the following most weakens this argument?

Accepted Answer

People who eat breakfast may also engage in other healthy habits that improve performance.

Answer

The study was conducted over only two weeks.

Answer

The office workers in the study were all in sedentary jobs.

Answer

Breakfast foods vary widely in nutritional content.

Answer

The study did not measure caloric intake throughout the day.

Question 3

An economist argues that raising the minimum wage will increase unemployment because businesses will hire fewer workers when labor costs rise. Which of the following, if true, most weakens this conclusion?

Accepted Answer

Higher wages increase consumer spending, which can create additional jobs.

Answer

Many minimum wage workers are teenagers living with their parents.

Answer

Some businesses operate in industries with thin profit margins.

Answer

The minimum wage has not been raised in over a decade.

Answer

Automation technology is becoming increasingly affordable.

Question 4

A school principal argues that eliminating recess will improve student academic performance because students will have more time for instruction. Which of the following most weakens this argument?

Accepted Answer

Research shows that physical activity improves concentration and cognitive function.

Answer

Students in other countries also have recess periods.

Answer

Some students use recess time to socialize rather than exercise.

Answer

Teachers need break periods as well as students.

Answer

The school day is already longer than the national average.

Question 5

A pharmaceutical company argues that its new drug is safe because none of the 200 participants in its clinical trial experienced serious side effects. Which of the following most weakens this argument?

Accepted Answer

Some serious side effects may only manifest after long-term use exceeding the trial duration.

Answer

The drug is intended to treat a rare disease.

Answer

Two participants experienced mild headaches during the trial.

Answer

The drug received approval in another country last year.

Answer

The trial was conducted at a single research hospital.

Question 6

A city planner argues that installing more streetlights in high-crime neighborhoods will reduce crime because criminals prefer to operate in darkness. Which of the following most weakens this argument?

Accepted Answer

Criminals may simply move their activities to adjacent unlit areas rather than stopping.

Answer

Streetlights are expensive to install and maintain.

Answer

Some crimes, such as fraud, occur indoors and are unaffected by lighting.

Answer

Residents in the neighborhoods support the streetlight initiative.

Answer

The city has successfully used streetlights to reduce crime in one previous instance.

Question 7

A manager argues that open-plan offices increase productivity because employees can communicate more easily with each other. Which of the following most weakens this argument?

Accepted Answer

Studies show that noise and interruptions in open offices reduce individuals' ability to focus on complex tasks.

Answer

Open-plan offices are less expensive to build than offices with private rooms.

Answer

Some employees prefer working from home.

Answer

The company recently hired 20 new employees who need workspace.

Answer

Communication technology allows employees to collaborate without being in the same room.

Question 8

An environmentalist argues that banning plastic bags will significantly reduce ocean pollution because plastic bags are a major component of ocean debris. Which of the following most weakens this argument?

Accepted Answer

Plastic bags account for less than 1% of ocean plastic by weight, with most coming from fishing nets and industrial waste.

Answer

Some plastic bags are made from recycled materials.

Answer

Many consumers have already switched to reusable bags voluntarily.

Answer

The ban would apply only to retail stores, not restaurants.

Answer

Paper bags also have environmental costs during production.

Question 9

A doctor argues that patients who follow Mediterranean diets have lower rates of heart disease, therefore the diet causes reduced heart disease risk. Which of the following most weakens this argument?

Accepted Answer

People who follow Mediterranean diets tend to live in regions with warmer climates and more active lifestyles.

Answer

The Mediterranean diet emphasizes olive oil, fish, and vegetables.

Answer

Heart disease is the leading cause of death in many Western countries.

Answer

The diet is difficult and expensive to maintain.

Answer

Several cardiologists have endorsed the Mediterranean diet.

Question 10

A tech executive argues that social media increases political polarization because users are exposed primarily to content that confirms their existing views. Which of the following most weakens this argument?

Accepted Answer

Research shows that political polarization has been rising since decades before social media existed.

Answer

Social media platforms use algorithmic feeds that prioritize engagement.

Answer

Many users follow accounts with opposing political viewpoints.

Answer

Social media companies have tried to reduce the spread of misinformation.

Answer

Younger generations use social media more than older generations.