Solved Examples for Inference - Verbal Reasoning for GMAT PDF Download

Q1: A candy company conducted market research through a survey and a subsequent taste test. In the survey, 27% of respondents said they preferred dark chocolate, 28% said they preferred white chocolate, and 45% said they preferred milk chocolate. But when the same group participated in a taste test of the company's new product line, 60% preferred dark chocolate.
Which of the following can be inferred from the information above?
(a) The survey participants were generally inaccurate regarding their chocolate preferences.
(b) Some people who stated a preference for white chocolate in the survey preferred dark chocolate in the taste test.
(c) Some people who stated a preference for milk chocolate in the survey preferred dark chocolate in the taste test.
(d) Some people who preferred milk chocolate in the taste test had initially stated a preference for white chocolate in the survey.
(e) Most participants expressed a different preference in the taste test than they had indicated in the survey.
Ans: (c)
Explanation: Dark preference rose from 27% to 60%, a net gain of 33 percentage points. Because only 28% initially preferred white chocolate, even if every white-chocolate supporter switched to dark (maximum 28%), that still would not produce the full 33% increase. Therefore at least 5% must have switched from milk to dark; that is, some people who stated a preference for milk chocolate in the survey preferred dark chocolate in the taste test. The other choices fail the "must be true" standard: (a) is plausible but not certain; (b) could be true but is not required; (d) and (e) go beyond what the numbers force.

Q2: Last year, more copies of accounting software programs were sold than in any previous year. For the first time ever, most of the copies sold were not sold to accountants but rather to individuals doing their own taxes or planning their own family budgets. However, the most-purchased copy of accounting software was a program designed for accountants performing corporate audits.
Which of the following is most strongly supported by the information above?
(a) More non-accountants purchased accounting software last year than in any previous year.
(b) Last year more accounting software was sold to corporations than in any previous year.
(c) Last year there were more copies of accounting software sold to non-accountants than in any previous year.
(d) At least some non-accountants purchased the most-purchased copy of software last year.
(e) Last year fewer copies of accounting software were purchased by accountants than in the previous year.
Ans: (c)
Explanation: The premises state two facts: (1) the total number of copies sold last year was the greatest ever, and (2) for the first time most copies were bought by non-accountants (a majority). Multiplying a greater total by a greater-than-50% share guarantees that the absolute number of copies sold to non-accountants last year exceeded that in any prior year. The incorrect options either conflate copies with purchasers (a), speculate about corporate purchases (b), cannot be proven from the facts (d), or overreach about accountants' purchases (e).

Q3: Gingivitis is a disease that occurs around the teeth and that can lead to periodontitis, a condition that causes tissue destruction in the gums and even tooth loss. Studies show that diets high in vitamin C can help to both prevent gingivitis and treat periodontitis.
Which of the following is best supported by the statements above?
(a) Increasing the amount of vitamin C in one's diet has helped some periodontitis patients reduce the severity of that condition.
(b) Periodontitis is a condition only contracted by those who have previously contracted gingivitis.
(c) People whose diets are high in vitamin C are less likely to contract periodontitis than those whose diet are low in vitamin C.
(d) A periodontitis treatment plan that does not include vitamin C is less effective than a plan that does.
(e) Some people suffering from periodontitis do so without having contracted gingivitis.
Ans: (a)
Explanation: The stimulus states that diets high in vitamin C can help prevent gingivitis and can help treat periodontitis. From this, it follows that increasing vitamin C has, at least in some cases, helped reduce periodontitis severity - that is exactly what "can help to treat" implies. Other choices go too far or are not established: (b) is too absolute (gingivitis "can" lead to periodontitis, not necessarily always), (c) is plausible but generalises beyond what the studies prove, (d) asserts a superiority that the passage does not establish, and (e) contradicts the given causal link without support.

Q4: A television news network has recently been criticized for failing to give as much time to individuals who do not believe climate change is occurring as they do to scientists who believe climate change is occurring, even though the network does give equal time to all sides of the debates over immigration, tax reform, and gun policy. The network claims that they only give equal time to both sides of a debate when one side cannot be definitively proven by existing scientific research.
Which of the following can be correctly inferred from the information given above?
(a) The television news network believes that it is important to avoid debate on scientific discoveries.
(b) If the news network gave the same time it gave to scientists to individuals who don't believe in climate change, it would increase its ratings.
(c) There are no effective counter arguments against climate change that might sway viewers to believe that climate change is not occurring.
(d) The television news network believes that the existence of climate change has been definitely proven by existing scientific research.
(e) No individuals who spoke on the network and who did not believe climate change was occurring were scientists.
Ans: (d)
Explanation: The network's stated policy is to give equal time only when one side cannot be definitively proven by scientific research. The network does not give equal time to climate-change sceptics, which implies that the network regards one side (the scientists who accept climate change) as definitively proven by existing research. That conclusion is the only one forced by the policy and the network's practice. The other choices either add unstated claims about motives, effects on ratings, or the identities of dissenting speakers and therefore are not guaranteed.

Q5: If the minimum wage increases again, MacDowell's will have to increase the prices it charges for its products. And if that happens, MacDowell's has a choice: it can spend more on advertising to attract more customers, or its sales and profitability will decrease. But since the extra advertising costs will simply raise total expenses, increasing those costs will still result in an overall decrease in profitability.
Which one of the following conclusions can be logically drawn from the statements above?
(a) MacDowell's will see its profitability increase if the minimum wage does not increase.
(b) MacDowell's will be unable to maintain its current profitability if the minimum wage increases.
(c) Unless the minimum wage increases, MacDowell's will continue to remain profitable.
(d) If MacDowell's sees a reduction in its profitability, that means that the minimum wage has increased.
(e) If the minimum wage increases, MacDowell's will no longer be able to remain profitable.
Ans: (b)
Explanation: The chain of reasoning is: a minimum-wage increase forces MacDowell's to raise prices; after raising prices MacDowell's either spends more on advertising or accepts lower sales and profitability. The advertising option still raises expenses and thus lowers profitability. Therefore, in every scenario that follows a minimum-wage increase, MacDowell's experiences a decrease in profitability and so cannot maintain its current profitability. The other choices overreach (a, c, e) or reverse causality (d) and are not guaranteed by the premises.

Q6: Barry's Barbecue is a restaurant chain that advertises itself as a safe place for diners with food allergies to eat. At Barry's, whenever a diner books a reservation and mentions a food allergy, the kitchen staff is prohibited from preparing multiple dishes on the same grill. This ensures that there is no cross-contamination between dishes, but also can result in longer wait times as fewer meals can be prepared than would be the case under normal circumstances.
Which of the following is best supported by the information above?
(a) Barry's will not make special kitchen accommodations for diners who do not make a reservation.
(b) Limiting cross-contamination from multiple dishes on the same grill is the most effective way to avoid issues for diners with food allergies.
(c) The kitchen staff at Barry's sometimes prepares multiple dishes on the same grill.
(d) Not all restaurants follow food allergy precautions to avoid cross-contamination between multiple dishes.
(e) Diners with food allergies are generally willing to be patient with longer wait times in order to avoid cross-contamination between dishes.
Ans: (c)
Explanation: The passage contrasts the allergy-related rule with "normal circumstances," stating that prohibiting multiple dishes on the same grill applies when an allergy is mentioned at reservation. That contrast implies that, under normal circumstances, the kitchen does prepare multiple dishes on the same grill; therefore it is correct to infer that the kitchen sometimes prepares multiple dishes on one grill. The other choices either state categorical policies not given (a), claim the precaution is the most effective (b), generalise about other restaurants (d), or assert customer attitudes without evidence (e).

Q7: Among the most effective ways to increase sales of an online service is to offer some form of free trial for users to experiment with before they purchase the full service. The benefit of such a practice is to encourage sales in individuals who would not buy the product without having tried it first.
Which of the following is best supported by the information given above?
(a) Because the cost of offering a free trial can be high, companies are often resistant to offering free trials, especially free trials that offer all features included within the paid version of the online service.
(b) The number of sales for a given online service is directly proportional to the number of visitors to the online service's website, a number that tends to increase if a free trial is offered.
(c) In calculating the total number of an online service sold, free trials are generally included as zero-dollar sales rather than as a separate category.
(d) Online services that are easily adapted to free trial versions sell better than do online services that are not readily distributed as free trials.
(e) The number of people who see the free trial as an acceptable replacement for buying the online service is not greater than the number of people who buy the online service because of their experience within the free trial.
Ans: (e)
Explanation: The passage defines the purpose of free trials: to convert people who would not buy the product unless they could try it. For free trials to serve that purpose, the number of users who treat the free trial as a substitute for purchase cannot exceed the number who are persuaded to buy because of the trial; otherwise the trial would defeat its own purpose. Thus (e) is the only choice that is guaranteed. The other options introduce unsupported claims about costs, proportionality, accounting conventions, or technical ease of offering trials.

Q8: Meditation can lead to reduced stress, increased concentration, and a longer life. And contrary to what many skeptics believe, regular meditation is more important than the duration of each session. While longer sessions produce better results, all the benefits listed above are possible from daily meditation sessions that are as short as ten minutes.
Which of the following is best supported by the statement above?
(a) Daily meditation sessions of an hour or longer can increase one's life expectancy.
(b) It is possible to achieve as much of a gain in life expectancy from ten minutes of meditation per day as from less frequent meditation sessions of an hour or longer.
(c) People who meditate for ten minutes each day will live longer than those who meditate less frequently.
(d) Mediation is only effective if it is performed on a daily basis.
(e) Meditating less frequently than once per day will lead to less positive benefits than meditating daily.
Ans: (a)
Explanation: The passage asserts that longer sessions produce better results and that benefits (including a longer life) are obtainable even from daily ten-minute sessions. From these statements it follows that longer sessions (for example, sessions of an hour) can also produce the benefit of increased life expectancy - hence (a) is supported. The other choices introduce unwarranted absolutes or comparisons: (b) and (c) make stronger comparative claims that are not established, while (d) and (e) assert exclusivity or strict ordering not given by the text.

Q9: Health insurance rates have been steadily increasing in this country for decades. Though health insurance companies paid for a smaller percentage of claims last year than they did ten years ago, the overall rise in the number of claims still means that more money is being paid out, and the companies compensate for this by hiking their rates.
From the information above, it can be inferred that ten years ago
(a) fewer people made health insurance claims than was the case last year.
(b) more claims were not paid by insurance companies than were not paid last year.
(c) health insurance companies paid a greater percentage of their claims than they paid twenty years ago.
(d) the percentage of health insurance claims that were unpaid was less than last year's percentage.
(e) profits made by health insurance companies were similar to profits made by health insurance companies last year.
Ans: (d)
Explanation: The stimulus explicitly states that insurers paid a smaller percentage of claims last year than they did ten years ago. That means the unpaid percentage was larger last year and, conversely, the unpaid percentage ten years ago was smaller than last year's. Therefore (d) follows directly. The other choices either conflate numbers of claims with numbers of claimants (a), reverse the numerical relation (b), bring in a period (twenty years) not discussed (c), or speculate about profits without sufficient evidence (e).

Q10: A computer equipped with fingerprint recognition software, which denies access to a computer to anyone whose fingerprint is not on file, identifies a person's fingerprint by analyzing not only the detailed structure of the fingerprint, but also such characteristics as the level of pressure upon which the finger is placed on the scanner and the finger's skin tone. Even the most adept computer hackers cannot duplicate all the characteristics the software analyzes.
Which of the following can be logically concluded from the passage above?
(a) Computers equipped with the recognition software will soon be installed in most financial firms that deal with sensitive electronic information.
(b) It is not possible for any top computer hacker to gain access to a computer equipped with the recognition software solely by virtue of skill in replicating the structure of fingerprints.
(c) The fingerprint recognition software is so sensitive that many authorized users are often denied legitimate access.
(d) Fingerprint recognition software has taken many years and tremendous investment to develop and perfect.
(e) Use of the recognition software is largely impractical due to the time it takes to record and analyze a fingerprint.
Ans: (b)
Explanation: The passage states the software checks several characteristics in addition to fingerprint structure, and that even the most skilled hackers cannot duplicate all of those characteristics. From that it follows that a hacker who duplicated only the fingerprint structure could not, by that action alone, gain access. The other options make claims about adoption, false rejection rates, development effort, or processing time that the passage does not establish and so cannot be concluded.