Heavy salting of Albritten's roads to melt winter ice and snow began

Question

Heavy salting of Albritten's roads to melt winter ice and snow began about 20 years ago. The area's groundwater now contains approximately 100 milligrams of dissolved salt per liter. Groundwater in a nearby, less highly urbanized area, where little salt is used and where traffic patterns resemble those of Albritten 20 years ago, contains only about 10 milligrams of dissolved salt per liter. Since water that contains 250 or more milligrams of dissolved salt per liter tastes unacceptably salty, continuing the salting of Albritten's roads at its present rate will render Albritten's groundwater unpalatable within the next few decades.

Which one of the following, if true, most seriously weakens the argument?

(A) Even water that contains up to 5,000 milligrams of dissolved salt per liter is safe to drink.

(B) The concentration of dissolved salt in Albritten's groundwater is expected to reach 400 milligrams per liter within a few decades.

(C) Salting icy roads is the simplest way to prevent accidents on those roads.

(D) Albritten's groundwater contained roughly 90 milligrams of dissolved salt per liter 20 years ago.

(E) Salting of Albritten's roads is likely to decrease over the next few decades.

Abhishek009 · Answer

Our goal is to weaken the highlighted part of the sentence - Show that continuing salting of Albritten's roads will not render Albritten's groundwater unpalatable (A) Safety is out of scope (B) Dissolved salt of 400 milligrams per liter will render Albritten's groundwater unpalatable (C) Simplest way of prevention of accident is out of scope of the discussion presented in the stimulus. (D) This is it If 20 years ago there was 90 milligrams of dissolved salt per liter Now after 20 years there is 100 milligrams of dissolved salt per liter Then within 20 years 10 milligrams of dissolved salt per liter has accumulated.. Or, within next 10 years (Decade) 5 milligrams of dissolved salt per liter will accumulate.. Now concentration of of salt is 100 milligrams of dissolved salt per liter In a decade at the same rate 5 milligrams of dissolved salt per liter will be added and thus the concentration will be 105 milligrams of dissolved salt per liter 105 milligrams of dissolved salt per liter < 250 or more milligrams of dissolved salt Thus salting Albritten's roads at its present rate will not render Albritten's groundwater unpalatable. (E) Reduction in rate of salting is a general comment and the statement can not attack the conclusiion... Hence answer will clearly be option (D) :-D

mvictor · Answer

if in 20 years, the level of salt increased by only 10 milligrams, or 5 milligrams in 10 years, then reaching another ~150 milligrams would take 300 years - clearly not within next few decades.

D is the best possible answer.

CrackverbalGMAT · Answer

let us simplify the argument -

Albritten salt level = 100 mg/l
less urbanized area salt level = 10 mg/l

if trend continues, then in a few decades
Albritten salt levels > 250 mg/l (hence, ground water will be unpalatable).

Option A - Incorrect.
We are not concerned with the safety of the water, but rather with its taste.

Option B - Incorrect.
this strengthens the argument. If it reaches more than 400 mg/l, then it will definitely be unpalatable within a few decades.

Option C - Incorrect.
We are concerned with "preventing accidents", but with whether the ground water is palatable or not.

Option D - Correct Answer.
If the salt levels were 90 mg/l 20 years ago, then they have risen only 10 mg/l over the past 20 years.
To reach 250 mg/l, it would take a couple of hundred years.

Option E - Incorrect.
Not relevant. Read the question carefully -  "continuing the salting of Albritten's roads  at its present rate  will render Albritten's groundwater unpalatable within the next few decades."

Whether they reduce the salting rates or not is irrelevant. Because the argument is concerned with - if the salting continues at its present rate.

bpiyush · Answer

A: above data can't be verified from the argument. out of scope
B: same as A out of scope
C: safety out of scope
D: sounds most rationale. Salt concentration was already 90 mgms 20 years before. So it is unlikely to reach 250 mgms very soon
E:Don't know about the future. Nothing like that in the argument.

IMO D

VerbalBot · Answer

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Heavy salting of Albritten's roads to melt winter ice and snow began

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