LSAT Logical Reasoning : Inference
Study concepts, example questions & explanations for LSAT Logical Reasoning
All LSAT Logical Reasoning Resources
Example Questions
Example Question #21 : Inference
The promise of this scientific research is that soon brainpower can be altered to better reflect the processes by which a computer sorts information. This will mean that rather than seeking to make computers more like humans, humans will move closer to being like computers.
Based on the information in the passage, it can be inferred that it must be true that __________.
computers use information in a way that directly relates to human brain functions
humans all wish to think much more like computer
humans do not fully understand how to think like computers
human brains and computers do not process information in the same manner
computerized methods of processing information are much less complex than human thought
human brains and computers do not process information in the same manner
The passage states that the research is trying to make human brainpower be more like a computer process. This means that what can be stated for certain based on the information in the passage is that computers and humans do not process information in the exact same way.
Example Question #22 : Determining Which Answer Must Be True Based On The Information Given
Most dachshunds have legs less than four inches long. Most dachshunds have long faces. Some animals with long faces make great pets. If an animal has legs less than four inches long, then it will not be a fast runner. Some animals are friendly.
If the statements above are true, then which one of the following must be true?
Most animals with long faces are Dachshunds.
Most animals with long faces make great pets.
Most great pets have long faces.
Most animals are friendly.
Some animals with legs less than four inches long have long faces.
Some animals with legs less than four inches long have long faces.
The answer is correct because there are overlapping "most" statements. From the stimulus, we can conclude that some animals with legs less than four inches long have long faces.
Example Question #21 : Must Be True
If all stores closed on Christmas Day, I would not have been able to buy groceries for dinner. If I had been unable to buy groceries, the children would certainly have cried. Fortunately, in the end, none of the children cried.
Which of the following conclusions can properly be inferred from the information above?
Some stores remained open on Christmas Day.
I purchased all of my groceries on Christmas Day.
If any of the children cried that night, I had been unable to buy groceries.
None of the stores remained open on Christmas Day.
No stores closed on Christmas Day.
Some stores remained open on Christmas Day.
By following the logic chain, it is clear that the children would have cried if none of the stores remained open. Since they did not cry, we know that at least some of the stores did stay open.
Example Question #21 : Inference
If a ruling party both reduces the unemployment rate and prevents major acts of terrorism, then the party’s rule will maintain power. A ruling party can still maintain power even if it does not maintain high levels of government spending. The current ruling party has not maintained high levels of government spending but has prevented major acts of terrorism.
If all the above statements are true, then which one of the following must be true?
The current ruling party has reduced the unemployment rate.
If the present administration reduces the unemployment rate, then it will maintain power.
If the ruling party keeps inflation low, then it will maintain power.
In order to maintain power, the ruling party must prevent minor acts of terrorism.
The current ruling party will not maintain power.
If the present administration reduces the unemployment rate, then it will maintain power.
Because the question is asking us what must be true, we are looking for an answer that is guaranteed to be correct under all situations. We do not know whether the current ruling party has reduced the unemployment rate and we do not know if the sufficient conditions for maintaining power have been met. We do however know that because the current ruling party has prevented major acts of terrorism, if they are able to reduce the unemployment rate, they will maintain power.
Example Question #22 : Inference
All scientists are studious. Some people who are studious are rich. If someone is rich they are able to live comfortably. Most people who are studious have trouble focusing.
If the above statements are true, all of the following must be true, EXCEPT
All people who are rich are able to live comfortably.
Some people who have trouble focusing are studious.
Some rich people are studious.
Some studious people are scientists.
Some scientists are rich
Some scientists are rich
The correct answer follows from the stimulus. It is the only answer that does not have to be true.
Example Question #21 : Inference
Every teacher expects their students to finish their homework. Any student that does not finish their homework gets detention. No student in detention is allowed to participate in school sporting events. All school sporting events take place on weekends.
Which of the following must be true?
No student that serves detention has violated their teachers' expectations.
No student that has completed their homework serves detention.
Every student that does not complete their homework cannot participate in weekend sporting events.
Every teacher expects their students to participate in school sporting events.
Every student that meets their teachers' expectations can participate in weekend sporting events.
Every student that does not complete their homework cannot participate in weekend sporting events.
This is the only answer the can truly be inferred from the information above. A student that does not complete their homework gets detention. Any student that gets detention cannot participate in sporting events, which take place on weekends.
Example Question #21 : Lsat Logical Reasoning
Two things are true of all good deeds. First, they are accompanied by feelings of satisfaction. Second, if they are publicly known, they elicit general approval.
If all of the above statements are true, then which of the following cannot also be true?
Every publicly known act that is accompanied by feelings of satisfaction is a good deed.
Some good deeds that are not publicly known are not accompanied by feelings of satisfaction.
Good deeds are good solely because they are accompanied by feelings of satisfaction.
Some publicly known deeds that elicit general approval are not accompanied by feelings of satisfaction.
Even if they frequently elicit general approval when known publicly, some deeds that are accompanied by feelings of satisfaction are not good deeds.
Some good deeds that are not publicly known are not accompanied by feelings of satisfaction.
According to sentences 1 and 2 of the passage, all good deeds are accompanied by feelings of satisfaction. Therefore the correct answer has to be false. That is, no good deed, whether or not publicly known, comes without satisfaction.
Example Question #1 : Determining Which Answer Cannot Be True Based On The Information Given
The price of a barrel of crude oil fell by 15 percent over the last month. Economists point to several causes, including the discovery of new reserves of oil, the increased accessibility of alternative sources of fuel, the growth of mass transit, the decline of car sales, and the increase in non-fuel-consuming means of transportation, such as bicycles, over the same time frame.
Which of the following does the above argument NOT imply?
The increased accessibility of alternative sources of fuel has reduced the demand for oil and thus driven the price of a barrel of crude oil down.
The discovery of new reserves of oil has increased the supply, created a surplus, and thus driven the price of oil down.
The growth of mass transit systems, which transport more people and use less fuel, has reduced demand for oil and driven the price of oil down.
People are more likely to purchase new cars if the price of oil is low.
If they have access to both, some people would rather use alternative sources of fuel instead of oil.
People are more likely to purchase new cars if the price of oil is low.
The argument can be said to imply all of the choices except that people are more likely to purchase new cars if the price of oil is low. In fact, the argument implies the opposite. There has been a decline in car sales over the last month, while the price of oil has gone down 15 percent. If there is any relationship between the two, it is not that low oil prices equates to more new car purchases. The argument implies, rather, that the decline of car sales contributed to the fall in the price of oil.
Example Question #1 : Determining Which Answer Cannot Be True Based On The Information Given
Fewer people go without email with each passing year. Not only are younger and younger children signing up for their own accounts, but the generation that was largely too old and out of touch to have ever had an account is slowly dying. It is entirely likely that no one over the age of 10 will be without an email account within the next ten years.
Which of the following statements cannot be true based on the above statement?
Older generations are much more likely than younger ones to adopt new forms of communication.
Email is used differently by specific age groups, leading to a diverse pattern of email usage.
Many younger people use many more communication methods than strictly email.
Older generations find email to be an awkward form of communication compared to letters and the telephone.
Email is a pervasive form of communication that is used by many different people.
Older generations are much more likely than younger ones to adopt new forms of communication.
The statement explicitly states that one of the reasons email will be essentially universal is that the older generation, which had never used email, would be dying out. This indicates that younger generations, which are only growing, are much more likely to adopt brand new forms of communication.
Example Question #1 : Cannot Be True
Many home renters buy their first homes believing that it is clearly more profitable to make mortgage payments than to pay rent. Other costs, such as maintenance, property taxes, and insurance must be factored in, however. All housing expenses together total at least 40% of most homeowners' income. It is not financially reasonable to spend any more than 30% of income on housing expenses.
If the information is correct, which of the following cannot be true?
The combination of property taxes, insurance, and home maintenance costs is greater than mortgage payments for a minority of homeowners
A majority of renters pay an unreasonable amount for housing expenses
A majority of homeowners have unreasonable housing expenses
A minority of homeowners have unreasonable housing expenses
A minority of homeowners have reasonable housing expenses
A minority of homeowners have unreasonable housing expenses
We know from the information given that most homeowners have housing expenses that are at least 40% of their incomes. If housing expenses of more than 30% of a homeowner's income is unreasonable, then at least a majority of homeowners have unreasonable housing expenses.
All LSAT Logical Reasoning Resources
