PrepTest 158

Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Main Point

Passage Summary:
Railroads rely more on automation now. Now, fewer railroad workers are needed. This reduces railroad operating costs. The amount of stuff shipped by rail will probably increase. Trucks are the main competitors of railroads. Trucks have not reduced their operating costs.

Strategy Overview:

1. Identify the conclusion
2. Identify the premises
3. Make sure the premises support the identified conclusion, and that the identified conclusion does not support anything else in the passage
4. Find the answer choice that restates the conclusion

Answer Anticipation:
Our job is straightforward on Main Point questions: find the main conclusion the author wants to convey. When searching for main conclusions, it helps to look for words associated with conclusions — like "therefore," "hence," and "thus" — or "shift" words — like "however," "but," and "nevertheless." Authors often use these words to introduce conclusions.

In this case, we can spot a conclusory phrase with "[t]his means that." That phrase is used to transition from a premise to a conclusion. It essentially means "the previous premise supports the following claim." Since the claim that follows "this means that" has support from the previous premise, it is a conclusion. So, we can note that the claim that "we can expect the volume of freight shipped by rail to grow" is probably this argument's conclusion.

That claim also makes a prediction. Certain claims are conclusory in nature. Statements that make a prescription, a selection, a judgment, or a prediction are usually conclusions. This gives us further confidence that the claim that "we can expect the volume of freight shipped by rail to grow" is probably this argument's conclusion.

To confirm that this claim is the conclusion, we need to identify the premises of this argument and verify that they all support that last sentence. As discussed, the previous claim that railroad operating costs have been reduced supports the prediction that the amount of stuff shipped by rail will probably increase. The statements about trucks also support the author's prediction. If trucks are railroads' main competitors, and trucks will probably not reduce their operating costs, railroads will have an edge on trucks. Railroads can offer cheaper shipping, and presumably, more people will ship by rail.

(The claim that "operating costs have been reduced" is a conclusion. It is the second part of a two-part sentence that begins with "[s]ince." That structure implies that the first part — "fewer railroad workers are needed" — supports the second part — that operating costs will be reduced. However, this claim is a premise/conclusion, not the main conclusion. It supports the author's main conclusion that we can expect that more stuff will be shipped by rail.)

So, the prediction that the amount of stuff shipped by rail will probably increase has support, which makes it a conclusion. And because that claim doesn't support any other statement in this passage, we know it's the main conclusion. Now, we just need to find the answer choice that expresses the same idea as the main conclusion. 

Answer Choice Explanation:
This is almost precisely what we anticipated. It captures the author's belief that "we can expect the volume of freight shipped by rail to grow." The author supports this belief, showing that railroads have reduced their operating costs through automation while their main competitor has not. So, this answer choice captures the main idea the author wants to convince us of. We can select (A) and move on to the next question.

Key Takeaway:
The phrase "this means that" is a conclusory phrase. It is used to transition from a premise to a conclusion. It essentially means "the previous premise supports the following claim." Since the claim that follows "this means that" has support from the previous premise, it is a conclusion. The phrases "this proves that" and "as a consequence" function similarly.

This answer choice describes two of the author's premises. It's true that reliance on automation means that fewer railroad workers are needed. However, the author uses this fact to support their prediction that the amount of stuff shipped by rail will probably increase. The author claims that the need for fewer railroad workers will reduce railroad operating costs, which makes it more likely that more people will ship cargo by rail — especially because railroads' main competitor will probably not reduce its operating costs.

This answer choice describes one of the author's premises. It's true that the trucking industry will probably not reduce its operating costs. However, the author uses this fact to support their prediction that the amount of stuff shipped by rail will probably increase. The author says that railroad operating costs will go down. So, if railroads' main competitor will probably not reduce its operating costs, railroads will have a competitive advantage over the trucking industry. Railroads can offer cheaper shipping; presumably, more people will ship by rail.

This is tempting, since it describes one the author's conclusions. However, this describes a premise/conclusion, not the author's main conclusion. The claim that railroads' operating costs have been reduced is supported by the premise that railroads' use of automation means that fewer railroad workers are needed. However, this claim supports the author's main conclusion that we can expect that more stuff will be shipped by rail. If railroads' operating costs are reduced, more people will probably ship cargo by rail — especially if railroads' main competitor does not reduce its operating costs.

This answer choice describes one of the author's premises. The trucking industry is indeed railway shipping's chief competitor. However, the author uses this fact to support their prediction that the amount of stuff shipped by rail will probably increase. The author says that railroad operating costs will go down. So, if railroads' main competitor will probably not reduce its operating costs, railroads will have an edge over the trucking industry. Railroads can offer cheaper shipping, so more people will probably ship by rail.