LSAT Logical Reasoning : Determining which answer is an assumption on which the argument depends

Study concepts, example questions & explanations for LSAT Logical Reasoning

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Example Questions

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Example Question #41 : Assumption

The government of a country mandates that all people who are citizens of that country vote in a general election and only people who are citizens shall vote. Therefore, no people who have immigrated to the country six months or less prior to the general election will vote in the general election, but some immigrants will vote in the general election.

The conclusion above follows logically if which of the following answers is assumed.

Possible Answers:

If you are an immigrant you are also a citizen of another country.

No person with dual citizenship can vote in the general election.

The process of becoming a citizen takes longer than six months.

Immigrants cannot become citizens.

The immigrants do not want to become citizens.

Correct answer:

The process of becoming a citizen takes longer than six months.

Explanation:

If the process of becoming a citizen takes longer than six months and only citizens can vote in the general election, then no person who has immigrated in the last six months can vote in the general election. The other answers are intended to throw you off. They all contain facts that are either not relevant, or contradictory of other facts.

Example Question #281 : Lsat Logical Reasoning

Some racecars have turbo boosted engines. Some non-racecars also have turbo boosted engines. A governmental agency mandated that all cars and racecars with turbo boosted engines have double-strap seat belts.

Assuming the above facts are true, which of the following must be true?

Possible Answers:

Some non-racecars have single strap seat belts.

All racecars have double-strap seat belts.

Most racecars have double-strap seat belts.

A car need not be a racecar to have double-strap seat belts.

There is no governmental agency mandate concerning racecars with single-strap seat belts.

Correct answer:

A car need not be a racecar to have double-strap seat belts.

Explanation:

This was a tricky question, many of the answers were intended to make you focus on facts that were not relevant. The text says only some, not all racecars have turbo boosted engines - and thus double-strap seat belts - therefore, not all cars have the double-straps and we do not know whether or not most racecars have the double strap. Concerning the non-racecars, it may be that there is not a single non-racecar that has a single strap seat belt, there is nothing prohibiting them from all having the double strap.

Example Question #282 : Lsat Logical Reasoning

Stanley University funds much of its well-known performing arts department with donations from wealthy alumni who are fans of the hockey team. Although the team has won the national championship nine out of the last ten years, this year it did not make it past the regional tournament, so unfortunately Stanley University will probably see fewer donations this year.

The above argument is true if we assume which of the following about Stanley University?

Possible Answers:

Alumni donors do not have as much money to contribute this year.

Stanley alumni donations depend partly on whether or not the hockey team wins.

The hockey team will not win without alumni donations.

The hockey team lost its star player and probably will not play in the championships again next year.

The reputation of the performing arts department at Stanley depends on whether or not the hockey team wins.

Correct answer:

Stanley alumni donations depend partly on whether or not the hockey team wins.

Explanation:

The question states that alumni donors are fans of the hockey team, but it does not explicitly state that they are only fans if the team wins.  The fact that a losing streak for the team would result in fewer donations only follows logically if we assume that these wealthy alumni are more likely to contribute when the hockey team is winning.  Some of the other choices could be true, but they are not necessary assumptions in order for the entire argument to be logical.

Example Question #283 : Lsat Logical Reasoning

Every professional athlete has had to work extremely hard to get where they are. In order to reach the elite heights of top level athletics, a person must never let up from constant training, effort, and planning.

A necessary assumption for the conclusion stated in the passage is __________.

Possible Answers:

athletes are among the most uniquely gifted people in society

athletes work harder at their profession than other groups of people

athletes cannot succeed at an elite level through talent alone

athletes are not able to devote much time to anything but their athletic pursuits

athletes are not separated very much by natural talent by other people

Correct answer:

athletes cannot succeed at an elite level through talent alone

Explanation:

The basic argument of the passage is that athletes must practice and train to an extreme degree in order to reach an elite level. The argument is only coherent and logical with the assumption that natural talent alone is not able to make an athlete reach an elite level, which makes it a necessary assumption.

Example Question #281 : Lsat Logical Reasoning

A medical degree is necessary for appointment to the hospital's board of directors. Further, no one having more than a five-percent equity stake in a pharmaceutical company can be appointed to the board of directors. Consequently, Dell, a practicing physician with a PhD in bioethics, cannot be appointed the hospital's treasurer, since he owns fifteen percent of PillCo, a pharmaceutical company.

The argument’s conclusion follows logically if which one of the following is assumed?

Possible Answers:

A PhD is not necessary for appointment to the position of treasurer.

Anyone with a medical degree who does not hold more than a five-percent stake in any pharmaceutical company is eligible for appointment to the hospital's board of directors.

Only those eligible for appointment to the hospital's board of directors can be appointed as the hospital's treasurer.

If Dell sold his stake in PillCo, he would be appointed treasurer.

PillCo is one of the hospital's pharmaceutical vendors.

Correct answer:

Only those eligible for appointment to the hospital's board of directors can be appointed as the hospital's treasurer.

Explanation:

To answer this question, it is necessary to recognize that while appointment criteria are set forth for the board of directors, they are applied to the position of Treasurer. We are never told that a Treasurer is a member of the board of directors. Thus, the conclusion is only warranted if eligibility for appointment to the board is a necessary condition for appointment to the position of Treasurer.

Example Question #284 : Lsat Logical Reasoning

The cheese on a frozen pizza, by the ounce, has the same amount of fat as the cheese on a pizza made at a restaurant. Therefore, the amount of fat in frozen pizza is the same as a pizza made at a restaurant.

The reasoning is flawed because the argument:

Possible Answers:

Argues that all cheese put on pizza has the same amount of fat.

Assumes that frozen pizza is exactly the same as pizza made in a restaurant.

Assumes that cheese is the only fat containing ingredient in pizza and that the amount of cheese in both pizzas is the same.

Overlooks that pizza made at four star restaurants is made with higher quality cheese than frozen pizzas.

Presupposes that all pizza is made with the same amount of cheese.

Correct answer:

Assumes that cheese is the only fat containing ingredient in pizza and that the amount of cheese in both pizzas is the same.

Explanation:

The question takes a statement about a specific quantity of cheese and applies it to the fat content of all pizzas. It does not consider that pizza can contain different amounts of cheese or that other ingredients may contain fat. The one fact contained in the reasoning, that all cheese on pizzas has the same amount of fat, may throw some people off.

Example Question #285 : Lsat Logical Reasoning

State legislators want to increase production in their state therefore they should provide temporary tax relief for businesses building new factories in the state. Temporary tax relief for businesses building new factories has been shown in other states to increase the number of businesses moving to that state.

The argument depends on the assumption that:

Possible Answers:

New factories in the state will bring more jobs to the state.

New factories in the state will not put existing factories out of business.

New businesses moving to the state increases productivity.

Tax relief is enough incentive to make businesses in neighboring states move location.

No neighboring states have tax relief incentives.

Correct answer:

New businesses moving to the state increases productivity.

Explanation:

The argument is assuming that increasing the number of businesses moving to the state will also increase productivity in the state. While this might not seem like an assumption because the tax relief incentive has worked in other states, there might be other factors in the state legislator’s state which affect the outcome of their plan.

Example Question #31 : Determining Which Answer Is An Assumption On Which The Argument Depends

Many people believe that abstract art has whatever meaning the viewer assigns to it.  However, objective evaluation of abstract art is not possible if this is true, because the aesthetic value of a piece of abstract art cannot be discussed unless at least two viewers agree on the meaning of the art.

Which of the following assumptions is required by the argument above?

Possible Answers:

Two people can judge that a piece of abstract art has aesthetic value only if they find the same meaning in the art.

If two or more viewers agree on the meaning of a piece of abstract art, then an objective evaluation of the art can definitely be made.

A piece of abstract art can only be evaluated objectively if its aesthetic value can be discussed.

Abstract art is created without an intended meaning by the artist.

The best way to objectively evaluate a piece of abstract art is through the agreement of more than two viewers.

Correct answer:

A piece of abstract art can only be evaluated objectively if its aesthetic value can be discussed.

Explanation:

A necessary assumption is one that, if negated, would render the argument logically incorect. It is needed in order to fill some sort of logical "gap" from premise to conclusion.  The current gap in the argument is the leap from being able to discuss the aesthetic value of art (for which agreement of at least 2 people about the meaning is necessary) to being able to evaluate art objectively. The correct answer fills this gap by making discussion of aesthetic value a necessary condition for objective evaluation.  If this were not the case, the entire justification for the argument's conclusion fails.

Example Question #287 : Lsat Logical Reasoning

Among the various models of racing cars used in top-level racing competitions, one cannot predict a car's ability to reach maximum speed simply by the horsepower of the motor.  The efficiency of a motor's fuel-injection system varies significantly, even between racing cars with motors of comparable horsepower.

The argument's conclusion is properly drawn if which one of the following is assumed?

Possible Answers:

For each race car, the efficiency of its fuel-injection system has a significant impact on how quickly it can reach maximum speed.

All cars that reach maximum speed within six seconds have comparable motors in terms of their horsepower.

It is not possible to assess how quickly a race car can reach maximum speed without knowing how powerful is its motor.

It is possible to infer the power of a car's motor by examining the efficiency of its fuel-injection system.

For any two race cars with comparable fuel-injection systems, the one with the more powerful motor will reach maximum speed more quickly.

Correct answer:

For each race car, the efficiency of its fuel-injection system has a significant impact on how quickly it can reach maximum speed.

Explanation:

The conclusion of this argument speaks to the ability to predict a race car's quickness in reaching maximum speed---horsepower alone won't permit an accurate prediction.  Why?  The argument states that the efficiency of the fuel-injection system varies among comparable cars.  This suggests that the fuel-injection system is a critical factor in a car's ability to reach maximum speed.  And that indeed is the unstated assumption.  The "efficiency of the fuel-injection system" is the key term in the evidence portion of the argument that is not stated in the conclusion, and it is that key term that must be contained in the assumption.  Any answer choice that does not mention that key term can be immediately eliminated.

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