WeakenDiff: Medium
Logic Breakdown
Passage Summary: Road salt has caused a significant spike in the saltiness of local water over the last two decades; if this trend continues, the water will soon cross the limit of what people find drinkable.
Conclusion: Continuing to salt the roads at the current rate will make Albritten's groundwater taste bad within a few decades.
Reasoning: Salt levels rose from 10 to 100 milligrams per liter over 20 years, and the threshold for unpalatable taste is 250 milligrams per liter.
Analysis: The argument assumes that the salt concentration will continue to increase at the same rate indefinitely. To weaken this, we need to find a reason why that trend might stop or slow down. For instance, if the groundwater eventually flushes out salt at a certain saturation point, or if the initial jump was due to a specific historical change that won't be repeated, the conclusion is undermined. Look for an answer that suggests the salt level will stabilize below the 250 mg/L threshold.
Conclusion: Continuing to salt the roads at the current rate will make Albritten's groundwater taste bad within a few decades.
Reasoning: Salt levels rose from 10 to 100 milligrams per liter over 20 years, and the threshold for unpalatable taste is 250 milligrams per liter.
Analysis: The argument assumes that the salt concentration will continue to increase at the same rate indefinitely. To weaken this, we need to find a reason why that trend might stop or slow down. For instance, if the groundwater eventually flushes out salt at a certain saturation point, or if the initial jump was due to a specific historical change that won't be repeated, the conclusion is undermined. Look for an answer that suggests the salt level will stabilize below the 250 mg/L threshold.
Passage Stimulus
Passage Redacted
Unlock Full Passage6.Which one of the following, if true, most seriously weakens the argument?
Correct Answer
D
D shows Albritten’s groundwater had ~90 mg/L 20 years ago, before heavy salting. That means the increase since salting began is only about 10 mg/L, undermining the idea that road salting is rapidly pushing levels toward 250 in the next few decades and weakening the projection.
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