Waste management companies, which collect waste for disposal in landfills and incineration plants, report that dispos...

Irina on August 26, 2019

@molinde,

Let's look at the stimulus:

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. It is clear that attempts to decrease the amount of plastic that people throw away in the garbage are failing.

Note that there are two ways a percentage of plastic in the mix could go up - (1) the actual amount of plastic has gone up; (2) the amount of other types of waste has gone down, then the percentage of plastic would go up even if the actual amount stayed the same.

This is a weaken question, so we are looking for an answer choice that would undermine the conclusion.

Let's look at the answer choices:

(A) Because plastics create harmful pollutants, an increasing percentage of the plastics handled by waste management companies are being disposed of in the landfills.

Incorrect. This fact has no impact on the validity of the conclusion. The argument tells us that the waste management company collects waste from both - landfills and incineration plans, it is irrelevant what proportion of waste comes from landfills.

(B) Although many plastics are recyclable, most of the plastics disposed of by waste management companies are not.

Incorrect. This fact has no impact on the validity of the conclusion. It is irrelevant whether the plastics are recyclable or not, we are only interested in the proportion of plastic in the mix.

(C) People are more likely to save and reuse plastic containers than containers made of heavier materials like glass or metal.

Incorrect. This fact is irrelevant, the fact that people are more likely to save and reuse plastic is not enough to infer anything about the amount of plastic people actually use and throw away.

(D) An increasing proportion of the paper, glass, and metal cans that waste management companies used to handle is now being recycled.

Correct. The argument attempts to explain the fact that disposable plastics make up an ever-increasing percentage of the waste management companies handle. This fact provides an alternative explanation, demonstrating that the proportion of other materials handled by waste management companies have gone down in relation to plastics. This fact weakens the conclusion that the amount of plastic must have gone up.

(E) While the percentage of products using plastic is increasing, the total amount of plastic manufactured has remained the same.

Incorrect. This fact is irrelevant. The argument is about plastic handled by waste management companies, not the amount of plastic manufactured.

masonolinde on August 26, 2019

Thank you!