- The conclusion follows logically if which one of the following is assumed?
Answer: Consumers using the monitor experience dangerous spikes only if they ingest at least 1 gram of sugar in a single serving.
The argument requires that spikes occur only when sugar intake is at least 1 gram; C guarantees that less than 1 gram prevents spikes. The other choices are irrelevant or already entailed by the premises.
- Every painting is an original. Every original is valuable. So every painting is costly. Which assumption suffices?
Answer: Every valuable work is costly
Every painting is valuable, since every painting is original and every original is valuable. To go from that to every painting being costly, you need the link that every valuable work is costly. The tempting wrong answer is 'every costly work is valuable,' but that just reverses the needed link and doesn't make all valuable works costly.
- An HR director argues that an employee should be promoted. The director notes that any employee who consistently exceeds quarterly targets and completes the leadership training program is eligible for promotion. The employee has consistently exceeded quarterly targets and has completed the leadership training program. Therefore, the employee is eligible for promotion, and so the employee should be promoted. The argument assumes that all employees who are eligible for promotion should in fact be promoted.
Which one of the following, if assumed, allows the conclusion of the argument to be properly drawn?
Answer: If an employee is eligible for promotion, then that employee should be promoted.
The HR director argues that the employee should be promoted, premised on a rule making those who exceed targets and complete training eligible, and the employee meeting those criteria, thus being eligible. The premises establish eligibility but don't prove promotion is required, leaving a gap between qualification and action. Answer A assumes that if eligible, the employee should be promoted, which bridges fully and guarantees the conclusion. Option D limits promotions to target-exceeders only, which narrows eligibility but doesn't mandate promoting all who qualify. A general insight is that sufficient assumptions often add 'should' to normative arguments, teaching us to spot when facts alone don't compel the recommended outcome.
- At a small museum, the director notes that last month every visitor who purchased an audio guide also bought a souvenir. The director also notes that this month, anyone who buys a souvenir must have spent at least $20 in the gift shop, and that all audio guides cost $8 and are sold only at the gift shop register. Therefore, anyone who purchases an audio guide this month will have spent at least $20 in the gift shop.
Which one of the following assumptions, if made, enables the conclusion to be properly drawn?
Answer: Anyone who purchases an audio guide this month also buys a souvenir this month.
The argument's goal is to prove that anyone purchasing an audio guide this month will spend at least $20 in the gift shop. The premises tell us that audio guides cost $8 and are sold only at the gift shop, and that anyone buying a souvenir this month must have spent at least $20 there—but these facts alone don't guarantee audio guide purchasers will reach the $20 threshold. The logical gap is that we don't know whether audio guide purchasers will buy anything else; the $8 audio guide alone won't reach $20. Answer (A) bridges this gap perfectly: if everyone who buys an audio guide also buys a souvenir, and souvenir buyers must spend at least $20, then audio guide buyers will definitely spend at least $20. Answer (E) might seem tempting because it also connects audio guides and souvenirs, but it reverses the relationship—it tells us souvenir buyers get audio guides, not that audio guide buyers get souvenirs, which is what we need. Remember that sufficient assumption questions require an answer that guarantees the conclusion with mathematical certainty, not just one that makes it likely.
- A recent study found that people who listen to classical music while studying scored higher on tests than those who did not. The researchers concluded that listening to classical music enhances cognitive performance. However, this conclusion may be unwarranted because the study did not account for the possibility that individuals who choose to listen to classical music are already more inclined to perform well academically. Which one of the following assumptions, if made, enables the conclusion to be properly drawn?
Answer: People who listen to classical music while studying are not inherently better students than those who do not.
This sufficient assumption question asks us to strengthen a causal argument about classical music enhancing cognitive performance. The researchers observed that classical music listeners scored higher on tests and concluded that classical music causes better performance. However, the argument acknowledges a critical gap: perhaps people who choose classical music are already better students (a selection bias problem). To make this causal conclusion logically certain, we need an assumption that eliminates this alternative explanation. Choice B directly addresses this gap by assuming that classical music listeners are not inherently better students than non-listeners. If we assume this, then the observed difference in test scores cannot be attributed to pre-existing academic abilities, making the causal conclusion about classical music valid. Choice A is too extreme, claiming classical music is the only factor affecting performance, which goes beyond what's needed. The key insight for sufficient assumptions is that they must completely eliminate alternative explanations that could undermine the causal relationship.
- A nonprofit director observes that when donors receive a personalized thank-you call within 48 hours, donor retention increases. The nonprofit began making such calls, and retention increased. Higher retention stabilizes revenue, and stable revenue allows the nonprofit to plan multi-year projects. Therefore, the thank-you calls will allow the nonprofit to plan multi-year projects.
Which one of the following, if assumed, allows the conclusion of the argument to be properly drawn?
Answer: If the nonprofit makes thank-you calls within 48 hours, then it will be able to plan multi-year projects.
The argument concludes that the thank-you calls will allow the nonprofit to plan multi-year projects. The reasoning chain shows that prompt thank-you calls increase donor retention, the nonprofit implemented calls and retention increased, and higher retention stabilizes revenue and enables long-term planning. The gap is proving that making thank-you calls will actually enable multi-year project planning, not just that retention increased. The correct answer fills this gap by stating that if the nonprofit makes thank-you calls within 48 hours, then it will be able to plan multi-year projects. Choice A connects retention increases to revenue stability but doesn't establish that the specific outreach strategy will enable project planning. Sufficient assumptions must create a direct causal bridge from the implemented practice to the organizational capability.
- A gardener claims that a certain lawn fertilizer caused the grass to turn greener. The gardener notes that whenever grass turns greener within a week of application, either the fertilizer caused it or the lawn received at least two inches of rain that week. The gardener also notes that the grass turned greener within a week of application. Therefore, the fertilizer caused the grass to turn greener.
The conclusion follows logically if which one of the following is assumed?
Answer: The lawn did not receive at least two inches of rain during that week.
The gardener wants to prove the fertilizer caused greener grass. The premise states that grass turning greener within a week means either fertilizer caused it OR the lawn got 2+ inches of rain, and we know the grass did turn greener within a week—but this alone doesn't prove which cause was responsible. The logical gap is that we need to eliminate the rain possibility to conclude it was the fertilizer; both explanations remain viable without more information. Answer (A) provides this elimination: if the lawn didn't receive 2+ inches of rain, then that option is ruled out, leaving only the fertilizer as the cause. Answer (D) might seem strong by making fertilizer the only possible cause, but this contradicts the premise that acknowledges rain as another cause—we need to work within the given framework. In "either/or" sufficient assumption questions, look for answers that eliminate one option rather than those that restructure the entire logical framework.
- The conclusion follows logically if which one of the following is assumed?
Answer: Both antibiotic X and antibiotic Y are effective against bacterium B.
If the only stocked options (X and Y) are both effective against B, then any prescription for B will be effective, as concluded. The other choices do not ensure that any prescribed antibiotic is effective against B.
- A museum director notes that whenever the museum extends weekend hours, attendance increases. The museum extended weekend hours last month, and attendance rose. Higher attendance leads to higher gift-shop revenue, and higher gift-shop revenue allows the museum to fund more educational programs. Therefore, extending weekend hours will allow the museum to fund more educational programs.
Which one of the following, if assumed, allows the conclusion of the argument to be properly drawn?
Answer: If a museum extends weekend hours, then it will be able to fund more educational programs.
The argument seeks to prove that extending weekend hours will allow the museum to fund more educational programs. The reasoning shows that extended hours increase attendance, the museum extended hours and saw attendance rise, and higher attendance leads to more gift-shop revenue and program funding. The gap is proving that extending hours will actually result in more educational program funding, not just that attendance increased. The correct answer bridges this gap by directly stating that if a museum extends weekend hours, then it will be able to fund more educational programs. Choice A connects attendance to gift-shop revenue, but this relationship is already established in the premises. The missing piece is the direct causal link from the specific action (extending hours) to the ultimate outcome (funding more programs).
- The conclusion follows logically if which one of the following is assumed?
Answer: Each household will install the LEDs to replace some of its existing incandescent bulbs next month.
The argument assumes households will actually replace incandescent bulbs with the provided LEDs. If each household does so, the cited study guarantees a citywide decrease; the other options do not ensure replacement or directly secure the conclusion.
- A retailer concludes that offering free shipping will increase online profits. She notes that many customers abandon their carts when they see shipping fees added at checkout. She also notes that when the retailer ran a weekend free-shipping promotion, the number of completed purchases rose. Therefore, she concludes that making free shipping permanent will increase profits. This reasoning assumes that the additional sales generated by free shipping will more than offset the retailer's increased shipping costs.
Which one of the following, if assumed, allows the conclusion of the retailer's argument to be properly drawn?
Answer: If free shipping increases completed purchases enough, then the resulting additional revenue will exceed the added shipping costs.
The retailer concludes that offering permanent free shipping will increase online profits, noting that customers abandon carts when seeing shipping fees and that a weekend free-shipping promotion increased completed purchases. The logical gap is between increasing completed purchases and increasing profits. The retailer assumes that the revenue gained from additional sales will exceed the cost of absorbing shipping expenses. Answer choice A provides this sufficient assumption: "If free shipping increases completed purchases enough, then the resulting additional revenue will exceed the added shipping costs." This directly guarantees that more sales will generate net profit despite higher costs. Answer choice D is tempting because it explains why shipping fees deter customers, but understanding customer psychology doesn't ensure that eliminating fees will be profitable overall. Sufficient assumptions must establish that the business outcome (profit increase) will actually occur despite the associated costs.
- Which one of the following assumptions permits the conclusion above to be properly drawn?
Answer: The only way for ash from a blanket deposit to be absent from dwellings now is that subsequent flooding removed it.
The conclusion leaps from 'no ash inside the dwellings' to 'flooding must be why.' For that leap to be valid, flooding has to be the ONLY possible reason the ash could be missing. The correct choice states exactly this: absence of blanket-deposited ash can only be caused by subsequent flooding. Grant that, and the conclusion is forced. The choice about flooding occurring centuries later is compatible with the argument but does not rule out other explanations for the missing ash, so it fails to make the conclusion follow. The choice about inhabitants sweeping ash out actually undermines the conclusion by offering a rival explanation. The choice about the timbers coming from cooking fires attacks the dating premise and is irrelevant to why ash is absent. The choice about field ash eroding faster than sheltered ash points the wrong way, suggesting interior ash should persist, which does nothing to justify the flooding claim. Only the first choice supplies the missing link that lets the conclusion be properly drawn.
- A doctor argues that sending patients automated text reminders will reduce missed appointments. She notes that many patients who miss appointments later say they simply forgot the time. She also notes that for a small group that already receives reminders, the no-show rate is lower than average. Therefore, she concludes that implementing text reminders for all patients will reduce missed appointments. The doctor's reasoning assumes that forgetting is the only reason these patients miss appointments, so that reminders would address the entire problem.
Which one of the following, if assumed, allows the conclusion to be properly drawn?
Answer: All missed appointments at the clinic occur because patients forget their appointment times.
The doctor argues that automated text reminders will reduce missed appointments, noting that patients who miss often say they forgot the time and that a small group receiving reminders has lower no-show rates. The logical gap is between addressing forgetfulness and solving the entire missed appointment problem. The doctor assumes that forgetting is the only reason patients miss appointments, so reminders would address all causes of no-shows. Answer choice A provides this sufficient assumption: "All missed appointments at the clinic occur because patients forget their appointment times." This guarantees that text reminders will address every case of missed appointments by targeting the sole cause. Answer choice D is tempting because it makes intuitive sense about forgetting and missing appointments, but it doesn't establish that forgetting is the only cause, so reminders might not address other reasons for no-shows. Sufficient assumptions must ensure the solution addresses the complete problem.
- A health organization claims that reducing sugar intake can significantly decrease the risk of developing diabetes. They base this claim on a study showing a correlation between high sugar consumption and increased diabetes rates. Which one of the following assumptions, if made, enables the conclusion to be properly drawn?
Answer: The study accounted for other dietary factors influencing diabetes risk.
The health organization concludes that reducing sugar intake decreases diabetes risk based on correlation between high sugar consumption and increased diabetes rates. The logical gap is that this correlation alone doesn't establish causation—other dietary or lifestyle factors might be the real cause. People with high sugar intake might also have poor overall diets, lack exercise, or have other unhealthy habits that actually cause diabetes. To make the causal conclusion about sugar specifically, we need to assume that other dietary confounding factors were controlled for. Choice C provides this assumption by stating the study accounted for other dietary factors influencing diabetes risk. This isolates sugar as the causal factor. Choice A addresses other risk factors but is too narrow, focusing only on people with lower sugar intake rather than ensuring proper experimental controls throughout the study.
- Which one of the following assumptions permits the conclusion above to be properly drawn?
Answer: Any report evaluated by the publisher's experts counts as peer-reviewed.
To apply the rule, the expert evaluation must amount to peer review; B supplies that equivalence, making the conclusion follow. The other choices do not establish that the report satisfies both required conditions.
- Which one of the following assumptions permits the conclusion above to be properly drawn?
Answer: Any candidate who debates the incumbent is independent.
From debating the incumbent, independence does not follow without an added link. Assuming debaters are independent, and given that independent candidates do not accept corporate donations, the conclusion follows. The other choices are irrelevant to that link.
- A city council member concludes that banning single-use plastic bags will reduce litter in local parks. She notes that park cleanup crews report that plastic bags are among the most commonly collected items. She also notes that when a neighboring town enacted a similar ban, local stores stopped distributing those bags. Therefore, she concludes that a ban in her city will reduce park litter. Her argument assumes that the plastic bags found in parks primarily come from local store distribution rather than from other sources that would continue unaffected.
Which one of the following, if assumed, allows the conclusion of the city council member's argument to be properly drawn?
Answer: Most plastic bags found as litter in the city's parks originated from local stores' single-use bags.
The city council member argues that banning single-use plastic bags will reduce park litter, noting that plastic bags are commonly found during park cleanups and that a neighboring town's ban stopped local store distribution. The logical gap is between stopping local store distribution and reducing park litter. The council member assumes that the plastic bags found in parks primarily come from local stores rather than external sources that would continue supplying bags after a local ban. Answer choice A provides this sufficient assumption: "Most plastic bags found as litter in the city's parks originated from local stores' single-use bags." This guarantees that eliminating the local source will significantly impact park litter. Answer choice B is tempting because it suggests behavioral change, but people switching to reusable bags doesn't necessarily mean fewer plastic bags will end up as litter if other sources continue. The assumption must establish that the ban targets the primary source of the problem.
- Which one of the following assumptions permits the conclusion above to be properly drawn?
Answer: Implementing the Neighborhood Patrol program is by itself sufficient to cause a drop in burglary within six months, even if other anti-burglary measures are reduced.
The argument concludes that burglary will drop, but it also tells you that funding for other anti-burglary measures will be cut. That is the gap: maybe the reductions elsewhere will offset any benefit from the program. The claim that the program by itself is sufficient to cause a drop within six months even when other measures are reduced closes exactly this gap, so the conclusion follows. That the budget cuts will later be restored does not help, because the drop must happen within six months and the argument is about the period of reduced funding. That the program is cheaper than other efforts speaks to cost, not to whether burglary actually falls. That our city resembles the evaluation communities in burglary patterns is tempting, but the evaluation communities were not described as cutting other measures, so similarity alone cannot guarantee the drop here. That residents will volunteer at high rates might help the program work, but it is not enough to overcome the possible loss from the cuts, so it does not make the conclusion properly drawn. Only the sufficiency claim guarantees the result despite the reductions.
- Which one of the following assumptions permits the conclusion above to be properly drawn?
Answer: All untampered contents can be safely consumed.
The gap is from untampered to safe; the premises give only safe-to-untampered, not the reverse. D supplies untampered-to-safe, which yields the conclusion. The other options are background or restatements that do not guarantee safety.
- A journal editor notes that articles subjected to double-blind peer review are cited more often than those that are not. The journal switched to double-blind review last year, and citations to its articles increased. More citations improve the journal's impact factor, and a higher impact factor attracts higher-quality submissions. Therefore, switching to double-blind review will attract higher-quality submissions to the journal.
Which one of the following, if assumed, allows the conclusion of the argument to be properly drawn?
Answer: If a journal switches to double-blind peer review, then it will attract higher-quality submissions.
This argument seeks to prove that switching to double-blind review will attract higher-quality submissions. The premises establish that double-blind review increases citations, the journal switched and citations increased, and more citations improve impact factor and attract better submissions. The logical gap is proving that the review process change will actually attract higher-quality submissions, rather than just showing that citations increased. The correct answer bridges this gap by stating that if a journal switches to double-blind peer review, then it will attract higher-quality submissions. Choice A connects impact factor increases to submission quality but doesn't establish that the specific review process change will attract better submissions. Sufficient assumptions must guarantee that the particular policy change will produce the desired outcome.
