QUESTION TEXT: Consumer magazine: Because front-loading washers use less …
QUESTION TYPE: Necessary Assumption
CONCLUSION: Front-loading machines require a special detergent in order to properly clean clothes.
REASONING: Ordinary powder detergent doesn’t fully dissolve in front loading machines.
ANALYSIS: Pay close attention anytime terms switch, especially when it seems “reasonable” to assume that they mean the same thing.
The evidence is that “powder won’t dissolve fully”. The conclusion is that “clothes won’t get fully clean”. That sounds reasonable, but who says powder needs to dissolve fully in order to clean clothes? That’s just an assumption the argument is making.
- Negate this: “One top loading machine in Mongolia uses half an ounce more water than other top loading machines”. That certainly doesn’t wreck the argument.
- Negate this: “A detergent designed for front loading washers also dissolves well in top loading washers”. That just shows that the detergent can work in both types. Great!
- This answer refers to all washing machines. So you could negate it by saying “Front loading machines require special detergent, but top loading machines can use any kind”. The argument is only about front loading machines.
- CORRECT. I don’t think this answer is properly formulated. I think it should have said “An ordinary powder detergent does not get clothes really clean unless it dissolves readily”. You could negate the answer as written by saying that liquid detergent doesn’t need to dissolve readily, but powder detergents do. That wouldn’t wreck the argument. That said, this is the best answer.
Negation: A detergent can get clothes really clean even if it doesn’t dissolve readily.
- We know that top loading washers use more water, and they may get clothes cleaner with ordinary detergent. But that doesn’t mean that more water is always good. Maybe there’s a washer that uses even more water but doesn’t work well.
Free Logical Reasoning lesson
Get a free sample of the Logical Reasoning Mastery Seminar. Learn tips for solving LR questions