LSAT Logical Reasoning › Determining which answer must be true based on the information given
As a society, we have no excuse for the prevalence of chronic dehydration. The remedy is simply too obvious and accessible. Those who suffer from the condition seek doctors’ opinions and medications, suffer from unexplained dizziness and other symptoms, and are susceptible to sickness. To solve these problems and to increase energy and focus, these people need only to drink more water—either by itself or as a primary ingredient in other beverages.
The information above provides the most support for which of the following statements?
Those who suffer from chronic dehydration could increase their energy and focus by drinking more water
Those who suffer from dizziness can adequately address the problem by drinking more water
Most people in the society at issue suffer from chronic dehydration
One can obtain all the health benefits of water by consuming it either by itself or as a primary ingredient in another beverage
Doctors do not advise chronically dehydrated patients to drink more water even though that would be the best remedy
The passage does not speak generally to the health benefits of water, the number of people affected by dehydration, or the impacts of dehydration. We can draw some conclusions, however, about the effects of drinking more water for those who are chronically dehydrated. Those who are chronically dehydrated will increase energy and focus by drinking more water.
Some of the college athletes playing football are also playing rugby, but none of them are playing soccer. Yet some of the soccer players are also playing rugby. For this reason, many coaches refer to rugby as the catch-all sport.
Which one of the following statements follows logically from the statements above?
There are some rugby players who play neither soccer nor football.
Some of the soccer players playing rugby also play football.
Most football players play only football and no other sport.
Most rugby players also play either soccer or football.
There are some rugby players who play soccer but not football.
Only three assertions are made in the paragraph: 1) no players play both football and soccer; 2) some players play both football and rugby; 3) some players play both soccer and rugby. There must be, therefore, a subset of players who play both soccer and rugby but not football.
If the bookstore does not respond to modern trends, it will not stay in business. And if the bookstore does not offer electronic books in a popular format, it will not respond to modern trends. Furthermore, no electronic book format is popular unless it can be used on each of the top three e-book readers.
If the statements above are true, which one of the following must be true?
If the bookstore stays in business, it will offer electronic books in a format which can be used on the top three e-book readers.
If the bookstore offers electronic books in a format which can be used on each of the top three e-book readers, it will stay in business.
It is significantly more likely that the bookstore will stay in business if it responds to modern trends than if it does not respond to them.
Popular electronic book formats generate more business for the bookstore than unpopular formats.
The bookstore will probably stay in business if it offers electronic books in a popular format.
The correct answer choice correctly notes that the bookstore will not stay in business unless it offers electronic books in a popular format as defined. Therefore, if the bookstore does stay in business, it must offer electronic books in such a format. The other answer choices employ incorrect information and/or probability reasoning unsupported by the argument. Remember: we do not know the conditions under which the bookstore will stay in business; we only know for certain what will cause the bookstore to not stay in business.
It appears that warm temperatures tend to improve both productivity and attitudes. Empirical evidence supports the general assumption that outdoor temperatures affect the way people feel and, perhaps as a result, the amount they get done. These conclusions are drawn from a recent study which found that when temperatures increase at the beginning of spring people are more likely to smile, make more money than in the winter, greet strangers, and report that they are content with their lives.
Which of the following is most supported by the study?
People are more likely to smile at the beginning of spring than at other times
When it is 80 degrees outside, people are more likely to smile than when it is 30 degrees
Those who smile often are likely to make more money than those who do not
Warm temperatures increase happiness and earnings
Those who greet strangers are likely to make more money and smile more often than those who do not
The study cited by the author does not directly support the author's conclusion. Instead, the study describes a few specific facts observed only at the beginning of the spring. The study supports the claim that people smile more often at the beginning of the spring than at other times, but it does not support broader claims about temperatures or seasons.
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?
If the present administration reduces the unemployment rate, then it will maintain power.
The current ruling party has reduced the unemployment rate.
The current ruling party will not maintain power.
In order to maintain power, the ruling party must prevent minor acts of terrorism.
If the ruling party keeps inflation low, 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.
Most standardized tests can only be mastered by studying prior test administrations. Though studying the abstract principles and concepts likely to be tested can improve a student’s score, there is no substitute for actual, concrete problems to get inside the minds of the test-makers. Indeed, if one studies a sufficient amount of prior tests, one will find that the very same problems are often repeated with minimal alterations.
The statements above, if true, most strongly support which one of the following?
At least some students taking standardized tests must study actual, concrete problems to master the tests.
A student need not study abstract principles or concepts to master standardized tests.
If a student studies a sufficient amount of prior tests, he or she will master the standardized test being taken.
Students must get inside the minds of the test-makers in order to achieve high scores on standardized tests.
Most standardized tests contain problems which are very similar to those given on prior administrations of the tests.
Because the statements indicate that most (not all) standardized tests can be mastered by studying prior test administrations with actual concrete problems, at least some students will need to do so to master those tests. The other answer choices either go too far in their inferences or misstate the premises given.
Observation of small groups in workplace environments has revealed important clues as to how leadership gets defined in offices. The person with the most experience or knowledge of the project does not automatically get thrust into a leadership position, but instead has to frequently take a backseat to the person who is loudest and most forceful in directing the actions of others.
Which of the following statements must be true based on the argument presented in the passage?
The most experienced and knowledgeable people do not always assert themselves as leaders.
A workplace situation is not an ideal environment in which to study leadership abilities.
Leaders in workplace situations work differently than leaders in other areas.
Leadership qualities are directly tied to experience and knowledge.
Workplace leadership is not easy to identify or comment on as a definable characteristic.
The passage states that leadership in a workplace environment is not based on anything except for an assertion of authority on the part of people who become leaders. Specifically, the passage notes people with knowledge and experience are not leaders. This means that it can be assumed that those with knowledge and experience do not always assert themselves as leaders.
A football player cannot be an All-American without both superior athletic talent and an unusual work ethic. Most football players have an unusual work ethic. However, most people with superior athletic talent do not play football, but rather other sports such as basketball. Most basketball players with superior athletic talent do not have an unusual work ethic.
If the statements above are true, which one of the following statements must also be true?
Most basketball players with superior athletic talent, if they played football, could not be All-Americans.
At least some All-American football players also play basketball.
Most football players with superior athletic talent could be All-Americans.
At least some basketball players with an unusual work ethic could be All-Americans if they played football.
Most football players could not be All-Americans.
The passage specifically states two necessary conditions for being an All-American in football: 1) superior athletic talent, and 2) an unusual work ethic. Because the passage notes that most basketball players who have (1) lack (2), it logically follows that most basketball players could not qualify as All-Americans in football, under the conditions stated. Note that the passage does not state the conditions sufficient to become an All-American football player; it merely states some necessary conditions. Nor does the passage tell us anything that would allow drawing a conclusion regarding “most football players” or “at least some All-American football players.”
Light bulb manufacturers have recently been forced to recall certain models of their LED bulbs due to overheating. The bulbs reportedly heated to the point that they produced smoke and fire, damaging customers’ lamps, walls, carpets, and other furniture. But many of these accidents could have been avoided had customers merely practiced energy conservation and turned off the lights when not in use. Indeed, according to one consumer study, over 90% of property damage from light bulb overheating occurs when no one is in the room to see what is happening.
The statements above, if true, most strongly support which one of the following?
Some property damage from light bulb overheating would likely not have occurred if more customers turned off their LED light bulbs when not in use.
If more customers had turned off their LED light bulbs when not in use, a recall of LED light bulbs would not have been necessary.
LED light bulbs are, according to customers, less safe than other types of light bulbs.
A light bulb is less likely to produce smoke and fire if a person is in the room during the period of time when it overheats.
When a customer’s lamp, wall, carpet, or other furniture has been damaged by an overheated light bulb, it is probable that the customer has not been practicing energy conservation.
The correct answer choice is basically a restatement of the second and third sentences of the passage. It is the only answer choice that does not make assumptions based on information not specifically given in the passage. It is unclear from the passage whether the recall could have been avoided or whether LED light bulbs generally are less safe than other light bulbs. Further, no clear conclusions can be drawn from the passage regarding the likelihood of an individual light bulb producing smoke and fire, or whether a customer has been practicing energy conservation.
Most students whose standardized test scores are high enough to warrant admission at a prestigious college also have a high grade point average. However, many students whose grade point average is high do not score high enough on standardized tests to warrant admission at a prestigious college. Some of these students, however, make up for the score deficiency by participating in extracurricular activities which the prestigious college values; colleges may accept slightly lower scores than normal if this is the case.
If the above statements are true, which one of the following statements must be true?
At least some students with a high grade point average obtained standardized test scores which are high enough to warrant admission at a prestigious college.
At least some students whose standardized test scores warrant admission at a prestigious college also participate in extracurricular activities which the prestigious college values.
Most students with a high grade point average do not need to participate in extracurricular activities to warrant admission at a prestigious college.
Most students who make up for their standardized test score deficiency by participating in extracurricular activities also have a high grade point average.
At least some students with a low grade point average do not score enough on standardized tests to warrant admission at a prestigious college.
If most students with high standardized test scores also have a high GPA, it must be true that at least some students with a high GPA also have high standardized test scores. The remaining answer choices, while they may be true, do not have to be true based on the statements in the passage. The passage does not tell us if students with high standardized test scores participate in extracurriculars, nor do we learn anything about students with low GPAs.