- PowerScore Staff
- Posts: 8950
- Joined: Feb 02, 2011
- Mon Jan 20, 2014 12:00 am
#40959
Complete Question Explanation
Justify the Conclusion, FL, #%. The correct answer choice is (B)
This question tests your ability to translate relationships into symbols and then make inferences from those symbolized relationships. Although some of them are conditional, as indicated by the sufficient condition “all” in the first and third sentences, others belong to a branch of logic called Symbolic, or “Formal,” Logic. The latter usually involves terms such as “some,” “most,” and “all.”
The structure of the argument can be diagrammed as follows:
The author then uses this evidence to conclude that there are more tools that are used for engraving than there are tools that are not used for engraving:
The question stem asks us to identify a statement that, if assumed, would enable to the conclusion to be properly drawn. Despite the word “assumed” here, this is a Justify rather than an Assumption question stem, because our job is not to identify a statement that is necessary for the conclusion to be true, but to prove the conclusion by adding a piece of information to the premises. The sufficient condition indicator (“if”) in the question stem is a reminder that you must select an answer that is sufficient to prove the conclusion by using the Justify Formula:
Premises + Answer choice = Conclusion
Also note that, unlike a typical Strengthen question stem in which the word “most” would weaken the force required of the correct answer, this question stem does not lessen the degree of justification required. Remember—because justifying a conclusion is such a specific task, the logic behind the question must allow for airtight provability. This makes most Justify stimuli contain either Conditional Reasoning or numbers and percentages. In this case, the stimulus contains both.
A quick glance at the argument reveals a gap between the premises and conclusion—just because all pin-tipped etching tools and some bladed etching tools are used for engraving does not necessarily mean that the total number of tools used for engraving is greater than the total number of tools not used for engraving. Imagine the following scenario:
To justify the conclusion, you must look for an answer establishing that the ratio of pin-tipped to bladed etching tools is at least equal. If so, given that all pin-tipped and at least some bladed tools are used for engraving, the total number of etching tools used for engraving will always be greater than the number of etching tools not used for engraving.
This prephrase is consistent with answer choice (B), which is the correct answer.
Answer choice (A): This answer choice is tantamount to a Mistaken Reversal of a premise, and can be diagrammed as follows:
ENG 
ET
Even if all the tools used for engraving were etching tools, that would not prove the conclusion. It is still quite possible that the total number of engraving tools is quite small, so that even if all of them are etching tools, only a small proportion of the tools are actually used for engraving.
Answer choice (B): This is the correct answer choice. If there the number of pin-tipped etching tools equals the number of bladed etching tools, then the number of etching tools used for engraving would always be greater than those not used for engraving. This is because all pin-tipped etching tools, plus some bladed tools, are used for engraving:
Since this answer choice adds a piece of information to the premises that is sufficient to prove conclusion, it is the correct Justify answer.
Answer choice (C): Just because no etching tool is both pin-tipped and bladed does not mean that there are as many pin-tipped etching tools as there are bladed etching tools. Since this answer choice does not indicate the ratio between pin-tipped and bladed etching tools, it is incorrect.
Answer choice (D): This answer choice may weaken the argument by implying that most bladed etching tools are not used for engraving (though some are). If this were true, it becomes even more likely that the number of etching tools used for engraving is no greater than the number of etching tools not used for engraving. Of course, we still do not know the proportion of pin-tipped to bladed etching tools. As a general rule, avoid answers to Justify questions that contain words such as “some,” “most,” or “majority of.” They are unlikely to provide you with the 100% degree of support required by the question stem.
Answer choice (E): This answer choice implies the following conditional relationship between engraving tools and bladed tools:
This does not prove the conclusion because there could be many more bladed etching tools than pin-tipped etching tools. Imagine the following scenario:
Justify the Conclusion, FL, #%. The correct answer choice is (B)
This question tests your ability to translate relationships into symbols and then make inferences from those symbolized relationships. Although some of them are conditional, as indicated by the sufficient condition “all” in the first and third sentences, others belong to a branch of logic called Symbolic, or “Formal,” Logic. The latter usually involves terms such as “some,” “most,” and “all.”
The structure of the argument can be diagrammed as follows:
- Premise: All etching tools are either pin-tipped or bladed.
Premise: Some bladed etching tools are used for engraving.
Premise: Some bladed etching tools are not used for engraving.
Premise: All pin-tipped etching tools are used for engraving.
Conclusion: There are more etching tools that are used for engraving than there are etching tools that are not used for engraving.
The author then uses this evidence to conclude that there are more tools that are used for engraving than there are tools that are not used for engraving:
The question stem asks us to identify a statement that, if assumed, would enable to the conclusion to be properly drawn. Despite the word “assumed” here, this is a Justify rather than an Assumption question stem, because our job is not to identify a statement that is necessary for the conclusion to be true, but to prove the conclusion by adding a piece of information to the premises. The sufficient condition indicator (“if”) in the question stem is a reminder that you must select an answer that is sufficient to prove the conclusion by using the Justify Formula:
Premises + Answer choice = ConclusionAlso note that, unlike a typical Strengthen question stem in which the word “most” would weaken the force required of the correct answer, this question stem does not lessen the degree of justification required. Remember—because justifying a conclusion is such a specific task, the logic behind the question must allow for airtight provability. This makes most Justify stimuli contain either Conditional Reasoning or numbers and percentages. In this case, the stimulus contains both.
A quick glance at the argument reveals a gap between the premises and conclusion—just because all pin-tipped etching tools and some bladed etching tools are used for engraving does not necessarily mean that the total number of tools used for engraving is greater than the total number of tools not used for engraving. Imagine the following scenario:
- ET = 100
PIN = 10, all used for engraving.
BLA = 90, of which 20 are used for engraving, and 70 are not used for engraving
To justify the conclusion, you must look for an answer establishing that the ratio of pin-tipped to bladed etching tools is at least equal. If so, given that all pin-tipped and at least some bladed tools are used for engraving, the total number of etching tools used for engraving will always be greater than the number of etching tools not used for engraving.
This prephrase is consistent with answer choice (B), which is the correct answer.
Answer choice (A): This answer choice is tantamount to a Mistaken Reversal of a premise, and can be diagrammed as follows:
ENG ETEven if all the tools used for engraving were etching tools, that would not prove the conclusion. It is still quite possible that the total number of engraving tools is quite small, so that even if all of them are etching tools, only a small proportion of the tools are actually used for engraving.
Answer choice (B): This is the correct answer choice. If there the number of pin-tipped etching tools equals the number of bladed etching tools, then the number of etching tools used for engraving would always be greater than those not used for engraving. This is because all pin-tipped etching tools, plus some bladed tools, are used for engraving:
Since this answer choice adds a piece of information to the premises that is sufficient to prove conclusion, it is the correct Justify answer.
Answer choice (C): Just because no etching tool is both pin-tipped and bladed does not mean that there are as many pin-tipped etching tools as there are bladed etching tools. Since this answer choice does not indicate the ratio between pin-tipped and bladed etching tools, it is incorrect.
Answer choice (D): This answer choice may weaken the argument by implying that most bladed etching tools are not used for engraving (though some are). If this were true, it becomes even more likely that the number of etching tools used for engraving is no greater than the number of etching tools not used for engraving. Of course, we still do not know the proportion of pin-tipped to bladed etching tools. As a general rule, avoid answers to Justify questions that contain words such as “some,” “most,” or “majority of.” They are unlikely to provide you with the 100% degree of support required by the question stem.
Answer choice (E): This answer choice implies the following conditional relationship between engraving tools and bladed tools:
This does not prove the conclusion because there could be many more bladed etching tools than pin-tipped etching tools. Imagine the following scenario:
- Pin-tipped tools = 10, all of which are used for engraving
Bladed tools used for engraving = 10
Tools not used for engraving = 30 (all are bladed)
You do not have the required permissions to view the files attached to this post.