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- Wed Apr 27, 2016 10:02 am
#23479
Complete Question Explanation
Must be True. The correct answer choice is (A)
The language in the question stem is not straightforward. We can see that the question asks us to find an answer choice that describes the situation in the stimulus. We will not be taking answer choices as true to see how the stimulus is affected. Basically, the facts in the stimulus will dictate other facts, one of which is the correct answer. This is a Must be True question even though the correct answer choice is about a mistake made in the reasoning.
We are told that the student has misinterpreted the professor, but this is not a Flaw in the Reasoning question. Both the stimulus and the answer choices involve conditional reasoning, and our task is to find the only logical phrase that would make sense in the context of the statements of the professor and the student. Putting the statement in our own words will make the job much easier.
The professor is saying that IF a type O man and a type O woman have a child THEN the child will be type O. The student responds by saying that the professor cannot be correct because the student has type O blood even though one of the student's parents has type B blood. For the student's sake, we hope this is not a logic class.
The student's faulty criticism makes sense only if he or she misinterpreted the professor's words to mean that anybody who has type O blood must have two type O parents. The combination of the student's O blood type and the student's father's B blood type is an attempt to provide a counterexample to this misinterpretation. The student is making a mistake with the directionality of the professor's statement; this is a mistaken reversal. Our prephrase is constructed by reversing the professor's comments without negation.
Answer choice (A): This is the correct answer choice, but the wording presents us with an extra layer of complexity. We should always be extra cautious when we see "only." If we had memorized our list of sufficient and necessary condition indicators, we could quickly see that this answer choice asserts that a pair of type O parents is the necessary condition and a type O child is the sufficient. However, we alternatively could test the language by testing hypothetical situations. Our prephrase was that a type O child was a sufficient indicator of O blood type in both parents. Considering this answer choice, could a type O child be the result of anything other than type O parents? No. "ONLY people with type O blood can have children with type O blood" means that even one non-O parent would prevent the birth of a type O child. Clearly, this is why the student feels no need to discuss his or her mother's blood type in attempting to rebut the professor. The difficulty with this answer choice lies in navigating through the language, but we should be satisfied that it is time well spent.
Answer choice (B): In the student's response, the parent has type B blood and the child has type O blood. There is no way that the student's comment would make sense if the student thought the professor was implying this answer choice.
Answer choice (C): The student has type O blood and a father with type B blood. If the student thought the professor was implying the situation of this answer choice, the student probably would simply nod his or head.
Answer choice (D): We have no reason to consider what "must also be true of all children" in a family because the student never mentioned any brothers or sisters. Moreover, this answer choice does not mention blood types at all. Cross this off and never look at it again.
Answer choice (E): Remember that the student has type O blood and a father with type B blood. Answer choice E mentions children with type B blood and is therefore irrelevant.
Must be True. The correct answer choice is (A)
The language in the question stem is not straightforward. We can see that the question asks us to find an answer choice that describes the situation in the stimulus. We will not be taking answer choices as true to see how the stimulus is affected. Basically, the facts in the stimulus will dictate other facts, one of which is the correct answer. This is a Must be True question even though the correct answer choice is about a mistake made in the reasoning.
We are told that the student has misinterpreted the professor, but this is not a Flaw in the Reasoning question. Both the stimulus and the answer choices involve conditional reasoning, and our task is to find the only logical phrase that would make sense in the context of the statements of the professor and the student. Putting the statement in our own words will make the job much easier.
The professor is saying that IF a type O man and a type O woman have a child THEN the child will be type O. The student responds by saying that the professor cannot be correct because the student has type O blood even though one of the student's parents has type B blood. For the student's sake, we hope this is not a logic class.
The student's faulty criticism makes sense only if he or she misinterpreted the professor's words to mean that anybody who has type O blood must have two type O parents. The combination of the student's O blood type and the student's father's B blood type is an attempt to provide a counterexample to this misinterpretation. The student is making a mistake with the directionality of the professor's statement; this is a mistaken reversal. Our prephrase is constructed by reversing the professor's comments without negation.
Answer choice (A): This is the correct answer choice, but the wording presents us with an extra layer of complexity. We should always be extra cautious when we see "only." If we had memorized our list of sufficient and necessary condition indicators, we could quickly see that this answer choice asserts that a pair of type O parents is the necessary condition and a type O child is the sufficient. However, we alternatively could test the language by testing hypothetical situations. Our prephrase was that a type O child was a sufficient indicator of O blood type in both parents. Considering this answer choice, could a type O child be the result of anything other than type O parents? No. "ONLY people with type O blood can have children with type O blood" means that even one non-O parent would prevent the birth of a type O child. Clearly, this is why the student feels no need to discuss his or her mother's blood type in attempting to rebut the professor. The difficulty with this answer choice lies in navigating through the language, but we should be satisfied that it is time well spent.
Answer choice (B): In the student's response, the parent has type B blood and the child has type O blood. There is no way that the student's comment would make sense if the student thought the professor was implying this answer choice.
Answer choice (C): The student has type O blood and a father with type B blood. If the student thought the professor was implying the situation of this answer choice, the student probably would simply nod his or head.
Answer choice (D): We have no reason to consider what "must also be true of all children" in a family because the student never mentioned any brothers or sisters. Moreover, this answer choice does not mention blood types at all. Cross this off and never look at it again.
Answer choice (E): Remember that the student has type O blood and a father with type B blood. Answer choice E mentions children with type B blood and is therefore irrelevant.