Using oil-based paints to paint walls or furniture requires the use of turpentine and each coat takes a long time to dry. Water-based paints dry quickly and can be cleaned from the hands or clothing with water alone. It can be concluded that water based paints are always better to use than oil-based paints.
Which of the following, if true, casts the most doubt on the argument's conclusion?
Incorrect.
[[snippet]]This answer choice strengthens the conclusion, but you are asked to weaken it. Stating that oil-based paints give off harmful fumes just gives us another reason to believe that water-based paints are always better.
Incorrect.
[[snippet]]This answer choice neither weakens nor strengthens the author's conclusion. The number of companies that produce each type of paint is irrelevant to our task of weakening the conclusion. Just because more companies produce oil-based paints does not mean they are better. Maybe all the companies that produce oil-based paints are failing. We need to focus on the argument, and find a statement that undermines the conclusion that water-based paints are always better to use.
Incorrect.
[[snippet]]This answer choice neither weakens nor strengthens the author's conclusion as knowing the popularity of do-it-yourself decoration does not help us choose between oil- and water-based paints, i.e., it does not help us undermine the conclusion.
Incorrect.
[[snippet]]This answer choice neither weakens nor strengthens the author's conclusion as knowing the method of painting a wall does not help us choose between oil- and water-based paints, i.e., it does not help us undermine the conclusion.
Good job!
[[snippet]]This answer choice weakens the conclusion directly by providing two negative characteristics of water-based paints. Since the conclusion states that water-based paints are always better to use, by bringing forward a situation where they do not perform well (moisture, direct sunlight) we can weaken this conclusion.