Here are the ten official questions which are discussed in detail in the Critical Reasoning - I module at the end of the Weaken Questions section. Shout out in the comments section if you have any doubts in the explanations.
Weaken Question No. 1
Traveler: Southern Airways has a far worse safety record than Air Dacentaria over the past few years, in terms of both the frequency of accidents and the severity of accidents. Therefore, although Air Dacentaria is slightly more expensive, I will choose it over Southern Airways for my flight from Pederton to Dacenta, since it is worth paying extra to have a safer flight.
Which of the following, if true, casts the most serious doubt on the travellers argument?
(A) Air Dacentaria's flight from Pederton to Dacenta is nonstop, whereas Southern Airways' flight touches down in Gorinda on the way.
(B) Most Southern Airways flights, but not its flight from Pederton to Dacenta, use Sarmouth airport, which because of its mountainous location is one of the world's most dangerous.
(C) For its flights from Pederton to Dacenta, Southern Airways uses a different model of airplane, with a smaller capacity, than the model Air Dacentaria uses for its flights on the same route.
(D) Only in the last few years has the cost of flying from Pederton to Dacenta been more expensive on Air Dacentaria than on Southern Airways.
(E) Although the frequency of accidents is greater on Southern Airways, on both airlines the proportion of flights that have accidents is very small.
Weaken Question No. 2
Kernland imposes a high tariff on the export of unprocessed cashew nuts in order to ensure that the nuts are sold to domestic processing plants. If the tariff were lifted and unprocessed cashews were sold at world market prices, more farmers could profit by growing cashews. However, since all the processing plants are in urban areas, removing the tariff would seriously hamper the government’s effort to reduce urban unemployment over the next five years.
Which of the following, if true, most seriously weakens the argument?
(A) Some of the by-products of processing cashews are used for manufacturing paints and plastics.
(B) Other countries in which cashews are processed subsidize their processing plants.
(C) More people in Kernland are engaged in farming cashews than in processing them.
(D) Buying unprocessed cashews at lower than world market prices enables cashew processors in Kernland to sell processed nuts at competitive prices.
(E) A lack of profitable crops is driving an increasing number of small farmers in Kernland off their land and into the cities.
Weaken Question No. 3
Mice that have been given morphine are very likely to develop blood poisoning because bacteria that normally reside in the intestine typically respond to morphine by migrating into the bloodstream. However, when mice are given both morphine and the new drug naltrexone, blood poisoning is much less frequent, although it does still occur. These results provide support for researchers’ prediction that naltrexone will turn out to be toxic to certain types of bacteria.
Which of the following, if discovered to be true, would most seriously weaken the support for the researchers’ prediction?
(A) After being administered to mice, naltrexone does not pass from the bloodstream into the intestine.
(B) Naltrexone inhibits morphine from triggering the migration of intestinal bacteria into the bloodstream.
(C) Mice that have been given naltrexone but not morphine have no greater risk of developing blood poisoning than do mice that have not been given either substance.
(D) The increased risk of blood poisoning is not the only harmful effect on mice of being given morphine.
(E) Conditions other than the presence of intestinal bacteria in the bloodstream can cause blood poisoning in mice.
Weaken Question No. 4
Twelve years ago and again five years ago, there were extended periods when the Darfir Republic's currency, the pundra, was weak: its value was unusually low relative to the world's most stable currencies. Both times a weak pundra made Darfir's manufactured products a bargain on world markets, and Darfir's exports were up substantially. Now some politicians are saying that, in order to cause another similarly sized increase in exports, the government should allow the pundra to become weak again.
Which of the following, if true, provides the government with the strongest grounds to doubt that the politicians' recommendation, if followed, will achieve its aim?
(A) Several of the politicians now recommending that the pundra be allowed to become weak made that same recommendation before each of the last two periods of currency weakness.
(B) After several decades of operating well below peak capacity, Darfir's manufacturing sector is now operating at near-peak levels.
(C) The economy of a country experiencing a rise in exports will become healthier only if the country's currency is strong or the rise in exports is significant.
(D) Those countries whose manufactured products compete with Darfir's on the world market all currently have stable currencies.
(E) A sharp improvement in the efficiency of Darfir's manufacturing plants would make Darfir's products a bargain on world markets even without any weakening of the pundra relative to other currencies.
Weaken Question No. 5
A major chemical spill occurred five years ago at Baker’s Beach, the world’s sole nesting ground for Merrick sea turtles, and prevented nearly all the eggs laid that year from hatching. Yet the number of adult female Merricks returning to lay their eggs at Baker’s Beach has actually increased somewhat since five years ago. Clearly, environmentalists’ prediction that the world’s Merrick population would decline as a result of the spill has proven unfounded.
Which of the following, if true, most seriously undermines the argument offered in refutation of the environmentalists’ prediction?
(A) The chemical spill five years ago occurred at a time when there were neither Merrick sea turtles nor Merrick sea turtle eggs on Baker’s Beach.
(B) Female Merrick sea turtles begin returning to Baker’s Beach to lay their eggs when they are ten years old.
(C) Under normal conditions, only a small proportion of hatchling female Merrick sea turtles survive in the ocean until adulthood and return to lay their eggs at Baker’s Beach.
(D) Environmental pressures unrelated to the chemical spill have caused a significant decline in the population of one of the several species of sea birds that prey on Merrick sea turtle eggs.
(E) After the chemical spill, an environmental group rejected a proposal to increase the Merrick sea turtle population by transferring eggs from Baker’s Beach to nearby beaches that had not been affected by the spill.
Weaken Question No. 6
The more viewers a television show attracts, the greater the advertising revenue the show generates. The television network Vidnet's most popular show, Starlight, currently earns the network's highest profits, but next year, because of unavoidable increases in production costs, its profits are projected to fall to below the average for Vidnet shows. Therefore, Vidnet would earn greater profits overall if it replaced Starlight with a show of average popularity and production costs.
Which of the following, if true, most seriously weakens the argument?
(A) The average profits of Vidnet shows have increased in each of the last three years.
(B) Shows that occupy time slots immediately before and after very popular shows tend to have far more viewers that they otherwise would.
(C) Starlight currently has the highest production costs of all Vidnet shows.
(D) Last year Vidnet lost money on a weekly show that was substantially similar to Starlight and was broadcast on a different day from Starlight.
(E) Even if, as a result of increased production costs, Starlight becomes less profitable than the average for Vidnet shows, it will still be more profitable than the average for television shows of all networks combined.
Weaken Question No. 7
Corporate Officer: Last year was an unusually poor one for our chemical division, which has traditionally contributed about 60 percent of the corporation's profits. It is therefore encouraging that there is the following evidence that the pharmaceutical division is growing stronger: it contributed 45 percent of the corporation's profits, up from 20 percent the previous year.
On the basis of the facts stated, which of the following is the best critique of the evidence presented above?
(A) The increase in the pharmaceutical division's contribution to corporation profits could have resulted largely from the introduction of single, important new product.
(B) In multidivisional corporations that have pharmaceutical divisions, over half of the corporation's profits usually come from the pharmaceuticals.
(C) The percentage of the corporation's profits attributable to the pharmaceutical division could have increased even if that division's performance had not improved.
(D) The information cited does not make it possible to determine whether the 20 percent share of profits cited was itself an improvement over the year before.
(E) The information cited does not make it possible to compare the performance of the chemical and pharmaceutical divisions in of the percent of total profits attributable to each.
Weaken Question No. 8
New grocery products benefit the manufacturer but not the grocer. If a company introduces a new brand of detergent, it might attract more consumers to its brand. The grocery store, however, will not sell any more detergent overall than it would have without the new brand. Thus there is little reason for grocers to encourage the introduction of new products.
Which of the following, if true, argues against the conclusion above?
(A) Often manufacturers introduce a new grocery product in order to take business away from a competitor who already produces a similar product.
(B) Some manufacturers prefer to put new grocery products in stores as early as possible, rather than spending time and money on controlled market research.
(C) Most grocery stores have such narrow profit margins that they cannot afford to carry marginally successful products.
(D) Grocers have the option not to take on products that they do not think will sell well, or that they expect will not increase the grocer's profits.
(E) Some manufacturers introduce new types of groceries, such as precooked meals that people can prepare quickly instead of going to a restaurant.
Weaken Question No. 9
Scientist: Cross-sections of stalactites - calcite formations deposited on cave ceilings by seeping water - can reveal annual variations in rainfall in particular areas over hundreds and thousands of years. We often found that when - according to these cross-sections - drought occurred in a particular area, it coincided with the collapse of an ancient society in that area. I hypothesize that drought reduced agricultural productivity in these areas, thereby leaving these societies without the resources needed to handle internal stresses and external threats.
Which of the following, if true, would most weaken the support for the scientist's hypothesis?
(A) Many droughts indicated in the cross-sections of stalactites do not correspond with the collapse of a society in that area.
(B) Information from the cross-sections of stalactites alone cannot reveal the level of agricultural output in an area at a particular time.
(C) Most of the societies that collapsed during droughts did so when internal power struggles coincided with military raids from neighboring societies.
(D) Most of the societies that collapsed during droughts maintained large stockpiles of food and water at the time of their collapse.
(E) Information from stalactites also suggests that the collapse of some societies coincided with periods of abnormally high rainfall.
Weaken Question No. 10
Tiger beetles are such fast runners that they can capture virtually any nonflying insect. However, when running toward an insect, the beetles intermittently stop, and then, a moment later, resume their attack. Perhaps they cannot maintain their pace and must pause for a moment's rest; but an alternative hypothesis is that while running tiger beetles are unable to process the resulting rapidly changing visual information, and so quickly go blind and stop.
Which of the following, if discovered in experiments using artificially moved prey insects, would support one of the two hypotheses and undermine the other?
(A) When a prey insect is moved directly toward a beetle that has been chasing it, the beetle immediately turns and runs away without its usual intermittent stopping.
(B) In pursuing a moving insect, the beetles usually respond immediately to changes in the insect's direction, and pause equally frequently whether the chase is up or down an incline.
(C) The beetles maintain a fixed time interval between pauses, although when an insect that had been stationary begins to flee, the beetle increases its speed after its next pause.
(D) If, when a beetle pauses, it has not gained on the insect it is pursuing, the beetle generally ends its pursuit.
(E) When an obstacle is suddenly introduced just in front of running beetles, the beetles sometimes stop immediately, but they never respond by running around the barrier.
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