Farmer: Because water content is what makes popcorn pop, the kernels must dry at just the right speed to trap the correct amount of water. The best way to achieve this effect is to have the sun dry the corn while the corn is still in the field, but I always dry the ears on a screen in a warm, dry room.

"Surprising" Phenomenon

Why does the farmer dry the kernels inside and not in the field?

Objective

A hypothesis resolving this discrepancy will state some advantage to drying the kernels indoors or some disadvantage to drying them in the field. This must be a good enough reason, in the farmer’s judgment, to dry the kernels indoors.

A
The region in which the farmer grows popcorn experiences a long, cloudy season that begins shortly before the popcorn in fields would begin to dry.

This explains why the farmer dries the kernels indoors. The weather is not sunny consistently enough for the sun to dry them in the field.

B
Leaving popcorn to dry on its stalks in the field is the least expensive method of drying it.

This widens the discrepancy. It is another reason for the farmer to dry the kernels in the field.

C
Drying popcorn on its stalks in the field is only one of several methods that allow the kernels’ water content to reach acceptable levels.

This is necessary for the farmer’s choice to be sound, but not enough to resolve the discrepancy. Sun drying is the most effective method, so the farmer’s decision not to use that method remains a mystery.

D
When popcorn does not dry sufficiently, it will still pop, but it will take several minutes to do so, even under optimal popping conditions.

This offers no reason for the farmer to dry the kernels indoors. It implies that improperly dried kernels are functional, but gives no disadvantage to sun drying and no advantage to drying indoors.

E
If popcorn is allowed to dry too much, it will not pop.

This is not a disadvantage of sun drying, which is the best way to ensure the kernels trap “the correct amount of water.” It is not stated whether indoor drying or sun drying produces kernels with more water.


7 comments

Factory manager: One reason the automobile parts this factory produces are expensive is that our manufacturing equipment is outdated and inefficient. Our products would be more competitively priced if we were to refurbish the factory completely with new, more efficient equipment. Therefore, since to survive in today’s market we have to make our products more competitively priced, we must completely refurbish the factory in order to survive.

A
fails to recognize that the price of a particular commodity can change over time

The manager doesn't mention that prices can change over time, but this doesn’t describe a flaw in her argument. Her argument addresses the price of her factory’s automobile parts compared to the price of other factories’ parts. Whether prices change over time is irrelevant.

B
shifts without justification from treating something as one way of achieving a goal to treating it as the only way of achieving that goal

The manager shifts from treating refurbishing the factory as one way of making products more competitively priced to treating it as the only way. In her premises “refurbishing” is a sufficient solution, while in her conclusion it’s a necessary solution.

C
argues that one thing is the cause of another when the evidence given indicates that the second thing may in fact be the cause of the first

The manager doesn’t make this mistake. Instead, she argues that one thing is necessary for another when her evidence indicates that it is in fact only sufficient.

D
recommends a solution to a problem without first considering any possible causes of that problem

The manager’s argument is actually flawed because it recommends— and even requires— a solution to a problem without first considering other possible solutions to that problem.

E
fails to make a definite recommendation and instead merely suggests that some possible course of action might be effective

The manager does make a definite recommendation: refurbishing the factory. She also establishes that refurbishing the factory would be effective at making products more competitively priced.


8 comments

Nutritionists believe that a person’s daily requirement for vitamins can readily be met by eating five servings of fruits and vegetables daily. However, most people eat far less than this. Thus, most people need to take vitamin pills.

Summarize Argument
The author concludes that most people need to take vitamin pills. This is because most people don’t hit their recommended intake of fruits and vegetables per day, which would be enough to satisfy their vitamin needs.

Notable Assumptions
The author believes that eating five servings a day of fruits and vegetables is a necessary rather than sufficient condition. This means the author assumes no other foods (grains, dairy, meats and alternatives) would satisfy these vitamin needs.

A
Even five servings of fruits and vegetables a day is insufficient unless the intake is varied to ensure that different vitamins are consumed.
Supposing this is true, most people still aren’t getting five servings of fruits and vegetables a day. We need to weaken the claim that those people need vitamin pills.
B
Certain commonly available fruits and vegetables contain considerably more nutrients than others.
Like (A), most people aren’t getting enough fruits and vegetables. We have no reason to believe the average person is eating especially nutrient-dense fruits and vegetables when they do eat those foods.
C
Nutritionists sometimes disagree on how much of a fruit or vegetable constitutes a complete serving.
Regardless of what constitutes a “complete serving,” the author tells us most people are eating “far less” than five servings. We don’t care about marginal disagreements among nutritionists.
D
Many commonly consumed foods that are neither fruits nor vegetables are fortified by manufacturers with the vitamins found in fruits and vegetables.
The author overlooks a class of foods that would satisfy vitamin requirements: fortified foods. If most people eat these, they don’t need vitamin pills.
E
Fruits and vegetables are also important sources of fiber, in forms not found in vitamin pills.
We don’t care about fiber. We need to weaken the claim that most people need vitamin pills.

15 comments

Sahira: To make a living from their art, artists of great potential would have to produce work that would gain widespread popular acclaim, instead of their best work. That is why governments are justified in subsidizing artists.

Rahima: Your argument for subsidizing art depends on claiming that to gain widespread popular acclaim, artists must produce something other than their best work; but this need not be true.

Summarize Argument: Counter-Position
Rahima counters Sahira’s argument by saying that Sahira's conclusion, that governments should subsidize artists, relies on the assumption that artists must produce lesser work to gain popularity. Rahima argues that this assumption isn't necessarily true.

Describe Method of Reasoning
Rahima argues that Sahira’s argument assumes that an artist’s best work can’t gain widespread popular acclaim. By pointing out this assumption and claiming that it isn’t necessarily true, Rahima undermines Sahira’s argument.

A
disputes an implicit assumption of Sahira’s
Rahima argues that Sahira assumes something that might not be true: that artists need to produce work that's not their best to gain popular acclaim. Rahima questions why an artist's best work can't also be popular. By disputing this assumption, she weakens Sahira's argument.
B
presents independent support for Sahira’s argument
Rahima doesn’t present any support for Sahira’s argument. Instead, she argues against Sahira’s assumptions.
C
accepts Sahira’s conclusion, but for reasons different from those given by Sahira
Rahima doesn’t state whether or not she agrees with Sahira’s conclusion that governments are justified in subsidizing artists. She also doesn’t provide any alternative reasons to support this conclusion.
D
uses Sahira’s premises to reach a conclusion different from that reached by Sahira
Rahima doesn’t use Sahira’s premises to reach a different conclusion. Instead, she questions a key assumption on which Sahira’s premises depend.
E
argues that a standard that she claims Sahira uses is self-contradictory
Rahima simply doesn't make this claim, nor does Sahira claim to adhere to any particular standard in the first place.

4 comments

Adult frogs are vulnerable to dehydration because of their highly permeable skins. Unlike large adult frogs, small adult frogs have such a low ratio of body weight to skin surface area that they cannot survive in arid climates. The animals’ moisture requirements constitute the most important factor determining where frogs can live in the Yucatán peninsula, which has an arid climate in the north and a wet climate in the south.

Summary
1. Adult frogs are vulnerable to dehydration due to their permeable skin.
2.*Small* adult frogs have a low body weight to skin surface area ratio, making them unable to survive in arid climates.
3. The Yucatán peninsula has an arid climate in the north and a wet climate in the south.
4. Frogs' moisture requirements are the most important factor determining where they can live in the Yucatán peninsula.

Strongly Supported Conclusions
Large adult frogs are better suited to live in the Yucatan peninsula than small adult frogs

A
Large adult frogs cannot coexist with small adult frogs in the wet areas.
This is too strong. The stimulus does not say that small and large frogs cannot coexist, only that large frogs are better suited to the environment.
B
Frogs living in wet areas weigh more on average than frogs in the arid areas.
There is not enough information to support this statement comparing the frogs’ weight. You need to make a lot of assumptions to make this work
C
Large adult frogs can live in more of the area than small adult frogs can.
The stimulus says that small adult frogs cannot survive in an arid climate. The Yucatan has an arid climate in the north. Thus, large adult frogs can live in more of the area than small adult frogs.
D
Fewer small adult frogs live in the south than do large adult frogs.
There is not enough support for this comparative statement. The stimulus does not give any information on how many frogs are in each region.
E
Small adult frogs in the south have less permeable skins than small adult frogs in the north.
There is no information to compare the permeability of small adult frogs in the south vs. the north.

9 comments

Automated flight technology can guide an aircraft very reliably, from navigation to landing. Yet this technology, even when functioning correctly, is not a perfect safeguard against human error.

"Surprising" Phenomenon
Automated flight technology is reliable, but still susceptible to human error.

Objective
The correct answer choice will be a hypothesis explaining how automated flight technology can still be affected by human error, even when the technology is functioning correctly.

A
Automated flight technology does not always function correctly.
We’re talking about automated flight technology that functions correctly.
B
Smaller aircraft do not always have their automated flight technology updated regularly.
Like (A), we’re talking about reliable, properly-functioning automated flight technology.
C
If a plane’s automated flight technology malfunctions, crew members have to operate the plane manually.
Like (A) and (B), the paradox is about why properly-functioning automated flight equipment is liable to human error. This talks about malfunctioning flight technology.
D
Some airplane crashes are due neither to human error nor to malfunction of automated flight technology.
This doesn’t show susceptibility to human error, which is what we need.
E
Automated flight technology invariably executes exactly the commands that humans give it.
Automated flight technology is entirely controlled by humans, and by extension liable to human error. One faulty human command can cause reliable, properly-functioning equipment to make mistakes.

3 comments