broall wrote:
Waste management companies, which collect waste for disposal in landfills and incineration plants, report that disposable plastics make up an ever-increasing percentage of the waste they handle. It is clear that attempts to decrease the amount of plastic that people throw away in the garbage are failing.
Which one of the following, if true, most seriously weakens the argument?
(A) Because plastics create harmful pollutants when burned, an increasing percentage of the plastics handled by waste management
companies are being disposed of in landfills.
(B) Although many plastics are recyclable, most of the plastics disposed of by waste management companies are not.
(C) People are more likely to save and reuse plastic containers than containers made of heavier materials like glass or metal.
(D) An increasing proportion of the paper, glass, and metal cans that waste management companies used to handle is now being
recycled.
(E) While the percentage of products using plastic packaging is increasing, the total amount of plastic being manufactured has remained unchanged.
Source: LSAT
Premise:
Disposable plastics are making up an ever-increasing percentage of the waste.
Conclusion:
Attempts to decrease the amount of plastic that people throw away in the garbage are failing
We need to weaken the conclusion. So we need to provide an explanation for how the amount of plastic people throw away may actually be decreasing. How can disposable plastic make up an ever increasing percentage of the waste then?
Say if waste were 100 tonnes. Disposable plastic - 50 tonnes (50%), Other - 50 tonnes
Now if waste is 60 tonnes, disposable plastic - 40 tonnes (66.6%), other - 20 tonnes
If "other" is decreasing faster than plastic, the percentage of plastic will increase even if the actual amount is decreasing.
(A) Because plastics create harmful pollutants when burned, an increasing percentage of the plastics handled by waste management
companies are being disposed of in landfills.
We are discussing the total amount of plastic that goes in landfills and is incinerated. So the split between them is irrelevant.
(B) Although many plastics are recyclable, most of the plastics disposed of by waste management companies are not.
Whether the plastic is recyclable or not is irrelevant. We are only concerned about the quantum of disposable plastic being handled by these companies.
(C) People are more likely to save and reuse plastic containers than containers made of heavier materials like glass or metal.
If people are more likely to reuse plastic, and not other materials, disposable plastic should not be making up an ever increasing percentage of waste. But our premise has to be true.
(D) An increasing proportion of the paper, glass, and metal cans that waste management companies used to handle is now being
recycled.
This says that more and more paper, glass and metal is being recycled. So less is going to the waste management companies. So it says that "other" may be decreasing quite a lot. So this could certainly imply that the amount of plastic that people throw away is decreasing but since other is decreasing more, the plastic makes up a higher percentage of the waste. This information certainly weakens our claim that people are not reducing the amount of plastic they are throwing. It is certainly possible that they are. Hence it weakens our conclusion.
We don't have to prove beyond doubt that the conclusion is wrong. We just have to sow a doubt.
(E) While the percentage of products using plastic packaging is increasing, the total amount of plastic being manufactured has remained unchanged.
The total amount of plastic being manufactured is irrelevant. We are only talking about disposable plastic that reaches waste management companies.
Answer (D)