Logical reasoning PrepTest 144 · Section 3 · Question 21

Incorrect. It doesn't matter if all the top loaders use the exact same amount of water. Some could use more than others, some less, as long as all use more than the front loading ones.

Incorrect. The special detergent has to dissolve more readily in front loaders than powder detergent does. It doesn't matter if this detergent works better in front loaders than top loaders.

Incorrect. This answer is too extreme in applying to all washing machines and setting out special detergent as a necessity for all machines. This answer also doesn't establish a connection between the special detergents and ready dissolution.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Strengthen with Necessary Premise

Stimulus Summary:
Front-loading washers don't dissolve powder detergent readily, so you need a special detergent to get clothes really clean.

Answer Anticipation:
In Strengthen with Necessary/Sufficient Premise questions, we should always be on the lookout for new terms in the conclusion. A new concept in the conclusion generally suggests a term shift, and the correct answer will connect this new term to something from the premises.

This argument brings up a brand new concept in the conclusion—getting clothes really clean with a special detergent. Why does it believe that this special detergent is necessary? Because ordinary powder detergent doesn't dissolve readily in these front-loading washers.

However, the argument never establishes that detergent has to dissolve readily in order to get clothes really clean—it assumes that connection. Therefore, we should look for an answer choice that establishes it as true.

Answer Explanation:
This answer establishes the connection between the premise and conclusion that the argument lacks. If a laundry detergent can get clothes really clean despite not readily dissolving in water, then the argument falls apart and it's no longer clear that the front loading machines need that detergent to get your clothes really clean.

Key Takeaway:
When dealing with a Strengthen with Necessary (or Sufficient) Premise question, be on the lookout for any new terms/concepts in the conclusion. These questions frequently feature a term shift with correct answers that connect a term from the premise with the new term in the conclusion.

Incorrect. The argument doesn't discuss how clean top-loading washers get clothes, so we don't know that they make clothes cleaner than front-loaders.