Heavy salting of Albritten’s roads

Answer choices

1. A

   Out of Scope: safe9% picked this

   Even water that contains up to 5,000 milligrams of dissolved salt per liter is

   The conclusion is saying that the water will be unpalatable (gross-tasting). It isn't saying the water will be unsafe to drink, so we can't weaken the argument by saying, "Even at 250mg, it'll still be safe."

   9%
2. B

   Strengthens1% picked this

   The concentration of dissolved salt in Albritten’s groundwater is expected to reach 400 milligrams per liter

   This answer more or less proves the conclusion true. Within a few decades the groundwater will be 400 mg / L. As soon as you hit 250+ mg / L, you get unacceptably salty water, so within a few decades we will indeed have unpalatable groundwater in Albritten.

   1%
3. C

   No Impact1% picked this

   Salting icy roads is the simplest way to prevent accidents on

   Whether salting icy roads is the simplest way, the 2nd simplest, the 14th simplest way doesn't matter. We're not debating whether or not we should salt the icy roads. This type of answer is trying to get students to 'hear' an additional conclusion. Actual conclusion: if we continue to salt at our present rate, in a few decades the groundwater will be unpalatably salty. Students hear additional conclusion: we should stop salting at our present rate That latter, imagined conclusion is a much broader claim that has to take into account all the positives and negatives of salting. For that conclusion, we would weaken by saying, "Sure, author, salting the road will make the groundwater salty, but remember it is the simplest way to prevent accidents, so it's worth the tradeoffs!" But we can only weaken the actual argument by arguing that in a few decades, even if we continue to salt at the current rate, the groundwater won't be unacceptably salty.

   1%
4. D

   Correct74% picked this

   Albritten’s groundwater contained roughly 90 milligrams of dissolved salt per liter

   Why this is right

   If 20 years ago the groundwater was 90mg/L, and 20 years of salting has brought it to 100mg/L, then salting roads at the current rate adds about 10mg/L every 20 years, or 5 mg/L every 10 years. Thus, a few more decades (30 years) would add another 15 mg/L to the groundwater, taking us up to 115 mg/L. The author is claiming in his conclusion that within 30 years, we'll have already passed by that 250 mg/L threshold for saltiness, but it looks like at the rate we're going, it would take 300 years to add another 150 mg/L to the groundwater. If this chart helps us visualize .... 20 yrs ago 90 mg Now 100 mg 20 yrs from now 110 mg 40 yrs from now 120 mg 60 yrs from now 130 mg etc. The author got himself confused by comparing the 100 mg/L level in Albritten to the 10 mg/L level in the nearby town. He started thinking that "prior to salting, Albritten was at that 10mg/L level". This answer destroys that assumption. It's saying, "Nope, prior to salting, Albritten was at 90 mg/L". So this is weakening by making the prediction in the conclusion sound way off. At our current rate, we won't hit unpalatable saltiness for about 300 years, not "within the next few decades".

   Skill tested: Weaken · how this choice captures the argument's function is the move to repeat next time.

   74%
5. E

   Irrelevant / Attacking the Trigger14% picked this

   Salting of Albritten’s roads is likely to decrease over the next

   This conclusion is making a prediction about a world in which we continue salting at our present rate. The only way to argue with such a conclusion is to say, "Nuh-uh ... in a world where we continue salting at our present rate, your prediction would NOT be true". We can think of this conclusion as a Conditional Conclusion: If we keep salting ? then within a few decades at the present rate unpalatable groundwater We can never strengthen a conditional conclusion by making the trigger seem more likely nor weaken a conditional conclusion by making the trigger seem less likely. We are assuming the trigger no matter what and trying to strengthen or weaken that the outcome would actually follow. If I say, "If Donald Trump ran for Prime Minister of Canada, he would win", you can't argue with me by saying, "He's ineligible to run for Prime Minister / he's not interested in governing Canada". You can only argue with me by accepting the hypothetical trigger and telling me how he would fail to win the Canadian election for Prime Minister.

   14%