Must Be True
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LSAT Logical Reasoning › Must Be True
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
Explanation
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.
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
Explanation
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.
Explanation
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.
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.
Explanation
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.
Explanation
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.
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.
Explanation
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
Explanation
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.
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
Explanation
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.
Explanation
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.
Explanation
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.