Q6 - Heavy salting of Albritten's roads

[LSAT-Chang]

I thought this question was quite tricky since I wasn't able to eliminate (E) since I thought it would weaken it as much as (D) would. I thought the underlying assumption was that these roads would continue to be salted at the present rate, so if we attack the assumption by stating that this activity is likely to decrease, then we can't really conclude that it will be unpalatable. Or maybe I'm missing a crucial component here. I would appreciate any feedback on this one. Thanks in advance

[chike_eze]

I thought this question was quite tricky since I wasn't able to eliminate (E) since I thought it would weaken it as much as (D) would. I thought the underlying assumption was that these roads would continue to be salted at the present rate, so if we attack the assumption by stating that this activity is likely to decrease, then we can't really conclude that it will be unpalatable. Or maybe I'm missing a crucial component here. I would appreciate any feedback on this one. Thanks in advance

This one is long and twisty. In the end, the faulty assumption is that the dissolved salt was built up entirely within the 20 year period. i.e, an average of 5mg/liter per year.

(D) weakens the argument by introducing the possibility a much lower rate. According to (D), over the 20 year period, dissolved salt per liter of water increased an average rate of 10 mg per liter in 20 years, i.e. only 0.5mg/liter per year.

> Therefore this weakens the assertion that in only a few decades, the amount of dissolved water/liter would have reached 250 mg/liter. Because of the higher likelihood of a lower rate/liter than 5mg/liter.

E.g.,
@ 5mg/liter = 30 years to get to 250 mg/liter
@ 1mg/liter = 150 years to get to 250 mg/liter

[LSAT-Chang]

Thanks a lot Chike, but could you kindly explain why (E) isn't correct??

[chike_eze]

Thanks a lot Chike, but could you kindly explain why (E) isn't correct??

The conclusion is that if the salting continues at its present rate, then the groundwater would be unpleasant to drink within a few years.

(E) says, the rate is likely to decrease over the next few years. This does not help or hurt the argument. We are concerned with the "current rate" of salting not a "decreased rate" of salting. In other words, we want to show that it doesn't necessarily follow that the current rate will lead to unpleasant drinking water.

Different argument, but take a look at this:

You almost got into an accident back there, if you continue driving at your current rate of speed, you will get a ticket in a few minutes.

(E) says you will likely decrease your speed in a few minutes.
> This does not weaken the argument. It doesn't strengthen it either. We are concerned with weakening the conclusion that your current speed will lead to a ticket.

If we show that the current rate is within the speed limit, then we weaken the conclusion you are likely to get a ticket (from speeding). You could still get a ticket though, maybe for reckless driving, but probably not for speeding.

[LSAT-Chang]

Wow, thanks for the GREAT explanation! I always thought that that type of answer choice would weaken it by showing that it won't rise at the current rate, but now I notice the conclusion is "IF it rises at the current rate, the water will taste unpleasant" so in order to weaken it, we could show that even if it rises at the current rate, it won't taste unpleasant, right? Just like how (D) gets at this by showing how for the past 20 years it has been salted at the current rate, but it doesn't taste unpleasant -- and your example illustrated this really well, since at first when I looked at it I thought "huh? knowing that i will reduce my speed in the next few minutes totally destroys the conclusion since then the author can't conclude that i will get in a ticket since I won't be driving at the current speed!" but the author is saying that "IF you drive at the current speed" not just blatantly saying that you WILL get it a ticket in a few minutes because you are driving so fast, right? I can see the difference -- it is just so hard to see since I feel like the author is purely concluding "you will get a ticket" when he/she is actually setting a condition in that it is true IF i drive at the current speed. So we need to destory the whole conclusion of "if you drive at the current speed, you will get a ticket" not just disprove the part of "you will get a ticket" right? Am I understanding this?

[mcrittell]

I actually don't understand what's happening in the stim, much less the ACs. Help, por favor!

[contropositive]

I read the discussions and although I find them helpful, I am still not certain why E is wrong. Here is what I thought:

water that contains 250+ milligrams of dissolved salt per liter tastes too salty. Therefore, continuing the salting of Albritten's road AT ITS PRESENT RATE will render Albritten's groundwater unappetizing within the next few decades.

It was hard for me to see the assumption here, but I am guessing he is trying to imply that in a few decades the groundwater will contain 250+ milligrams of dissolved salt because of its current rate.

D would be saying it only increased by 10 milligrams since 20 years ago, which I know implies a slow rate. However, the author said "continuing it at its present rate will render the groundwater" does it really matter that it only increased by 10 milligrams from 20 years ago? what if the author has a problem with this 10 milligrams too? we don't really know much about its present rate, we only know that it currently contains 100 milligrams. So what if it only increased by 10? in a few decades it will go up and the author has a problem with it reaching 250+

I am really confused about this...:/

[rinagoldfield]

Great discussion, all. (E) is definitely tempting



Let's start with the argument core.

Premises:

Road salting is correlated with high groundwater salt levels in A.

+

Really salty water is undrinkable



Conclusion:

If A. continues to salt its roads at its present rate, the groundwater will soon be undrinkable.



The essential flaw here is that the author mistakes causation for correlation. He assumes that the road salting is CAUSING the high groundwater salt. But this isn’t necessarily the case; perhaps A. has naturally salty water. If A. has naturally salty water, then the road salting won’t affect anything.



(D) gets at this flaw. It weakens the assumed causal relationship between road salting and groundwater salt by suggesting that A. has naturally salty roads.

To your question, royaimani, you are right that choice D leaves room for a 10 mg/20 year effect of the road salting. But at that rate, there is no way for the groundwater to reach 250 mg level of saltiness in a few decades.

(E) is outside of the parameters of the argument. The argument concerns what will happen if A. continues salting at its present rate, not what will happen if it decreases this rate.

Hope this helps!