Self-study
Heavy salting of Albritten's roads to melt winter ice and snow began about 20 years ago. ███ ██████ ███████████ ███ ████████ █████████████ ███ ██████████ ██ █████████ ████ ███ ██████ ███████████ ██ █ ███████ ████ ██████ █████████ █████ █████ ██████ ████ ██ ████ ███ █████ ███████ ████████ ████████ █████ ██ █████████ ██ █████ ████ ████████ ████ █████ ██ ██████████ ██ █████████ ████ ███ ██████ █████ █████ ████ ████████ ███ ██ ████ ██████████ ██ █████████ ████ ███ █████ ██████ ████████████ ██████ ██████████ ███ ███████ ██ ███████████ █████ ██ ███ ███████ ████ ████ ██████ ███████████ ███████████ ███████████ ██████ ███ ████ ███ ████████
Summarize Argument
Albritten’s groundwater will be unsuitable for consumption in the coming decades if its roads continue to be heavily salted. This is because water with more than 250 milligrams of dissolved salt per liter is unpalatable and currently, Albritten’s groundwater has about 100 mg of dissolved salt per liter. In comparison, the groundwater in a nearby area that isn’t heavily salted has about 10 mg of dissolved salt per liter.
Notable Assumptions
The author assumes that the heavy salting of Albritten’s roads caused an increase in the salt concentration of its groundwater. By doing so, the author also assumes that the groundwater did not always have a high amount of dissolved salt per liter and that the cause of an increase is not some other factor (such as the highly urbanized nature of Albritten or traffic—two characteristics that the other area also lacks).
6.
Which one of the following, ██ █████ ████ █████████ ███████ ███ █████████
a
Even water that ████████ ██ ██ █████ ██████████ ██ █████████ ████ ███ █████ ██ ████ ██ ██████
This does not affect the argument. The author is not concerned with whether the water is safe to drink, but with whether the water is palatable (i.e., whether it tastes unacceptably salty).
b
The concentration of █████████ ████ ██ ███████████ ███████████ ██ ████████ ██ █████ ███ ██████████ ███ █████ ██████ █ ███ ████████
This strengthens the argument. It reinforces the idea that Albritten’s groundwater will become increasingly salty in the coming decades and thus, will become unpalatable. 400 mg per liter is much higher than 250, which is the concentration at which water becomes unpalatable.
c
Salting icy roads ██ ███ ████████ ███ ██ ███████ █████████ ██ █████ ██████
This does not affect the argument. The author is not concerned with why the salting occurs, but with the consequences of the heavy salting.
d
Albritten's groundwater contained ███████ ██ ██████████ ██ █████████ ████ ███ █████ ██ █████ ████
This weakens the argument. It exploits the author’s assumption that the salt concentration of Albritten’s groundwater has increased because of heavy salting. (D) says the groundwater has always been salty—much saltier than the nearby area that does not heavily salt its roads.
e
Salting of Albritten's █████ ██ ██████ ██ ████████ ████ ███ ████ ███ ████████
This does not affect the argument. The author only makes an argument about the consequences if Albritten’s roads continue to be heavily salted. The roads not being salted at the current rate is outside the scope of the author’s argument and is not relevant.