Researcher: Hard water contains more calcium and magnesium than soft

Question

Researcher: Hard water contains more calcium and magnesium than soft water contains. Thus, those who drink mostly soft water incur an increased risk of heart disease, stroke, and hypertension, for people being treated for these conditions tend to have lower levels of magnesium in their blood.

Which one of the following, if true, most undermines the researcher’s argument?

(A) Magnesium deficiency is not uncommon, even in relatively prosperous countries with an otherwise generally adequate diet.

(B) Magnesium is needed to prevent sodium from increasing blood pressure.

(C) As people age, their ability to metabolize magnesium deteriorates.

(D) The ingestion of magnesium supplements inhibits the effectiveness of many medicines used to treat high blood pressure and heart disease.

(E) Compounds commonly used to treat hypertension and heart disease diminish the body’s capacity to absorb and retain magnesium.

Bunuel · Accepted Answer

EXPLANATION FROM Fox LSAT

The first premise is the first sentence: Hard water contains more calcium and magnesium than soft water. The second premise is found in the last two lines: People being treated for heart disease, stroke and hypertension tend to have lower levels of magnesium in their blood. The conclusion is: Those who drink mostly soft water incur an increased risk of heart disease, stroke, and hypertension.

Does this really add up? I don’t think so. This seems to be a correlation-therefore-causation flaw. The premises indicate that there is a correlation between low blood magnesium and being treated for certain diseases. But this doesn’t mean that low blood magnesium  causes  certain diseases. In fact, it’s entirely possible that the diseases cause low blood magnesium, or that some third factor (living near a power plant?) causes both low blood magnesium and the diseases. This logic simply doesn’t stand up. I’m pissed. And that’s always a good thing on the Logical Reasoning.

The question asks us to undermine, the researcher’s argument. I’ve already been doing that. Let’s see what we’ve got in the answer choices.

A) Just because magnesium deficiency is not uncommon does not mean that it doesn’t cause diseases. This isn’t it.

B) This, if true, might  strengthen  the argument because it indicates how low blood magnesium might cause diseases. We’re looking for a weakener, so this is out.

C) At first I thought age was irrelevant, but then I thought that maybe age is the third factor that causes the apparent correlation. If age causes low blood magnesium, and age causes diseases, then this could be a weakener. My only problem here is that I’m not sure if a bad metabolism would lead to low blood magnesium or  high  blood magnesium. Which means this answer could strengthen or weaken. Hmm. I could pick this if D and E are both bad, but I’m definitely hoping for something better.

D) This just jumbles all the concepts up together and I’m not sure what it would mean, logically. If magnesium supplements inhibit your heart medicine, then you’ve already  got  heart disease. So this is probably irrelevant.

E) I think this is it. This is one of our predictions, right? We said, “The diseases cause low blood magnesium,” which could happen via the medications that you have to take for the diseases, right? If this is true, then it indicates that the correlation has a  reversed  cause and effect from what the argument assumed. So this is a pretty devastating weakener. Reversal of cause and effect is also a very common correct answer on the LSAT.

Let’s go with E.

sudarshan22 · Answer

Cause   : Low level of Magnesium 
  Effect   : Heart Disease
 
(A) Magnesium deficiency is not uncommon, even in relatively prosperous countries with an otherwise generally adequate diet. -->  Irrelevant

(B) Magnesium is needed to prevent sodium from increasing blood pressure. -->  Strengthen

(C) As people age, their ability to metabolize magnesium deteriorates. -->  Irrelevant

(D) The ingestion of magnesium supplements inhibits the effectiveness of many medicines used to treat high blood pressure and heart disease.-->  Irrelevant

(E) Compounds commonly used to treat hypertension and heart disease diminish the body’s capacity to absorb and retain magnesium. -->  Correct, Weakens the argument by stating that the effect could be the cause instead

Hence,  E .

warrior1991 · Answer

The conclusion is that those who drink mostly soft water would incur an increased risk of heart disease, stroke, and hypertension.

The evidence put forward is :  
1.For people being treated for these conditions tend to have lower levels of magnesium in their blood.
2.Hard water contains more calcium and magnesium than soft water contains.

We have to weaken the conclusion saying that it is not because of soft drinking water that people would incur an increased risk of heart disease, stroke, and hypertension.

(A) Magnesium deficiency is not uncommon, even in relatively prosperous countries with an otherwise generally adequate diet.
 Irrelevant.

(B) Magnesium is needed to prevent sodium from increasing blood pressure.
 This is strengthening the claim. If magnesium is needed then those who drink soft water would incur am increased risk.

(C) As people age, their ability to metabolize magnesium deteriorates.
 This will be applicable to both hard water drinkers and soft water drinkers. So this is irrelevant.

(D) The ingestion of magnesium supplements inhibits the effectiveness of many medicines used to treat high blood pressure and heart disease.
 This will be applicable to both hard water drinkers and soft water drinkers. So this is irrelevant.

(E) Compounds commonly used to treat hypertension and heart disease diminish the body’s capacity to absorb and retain magnesium.
 This reverses the cause and effect. This says that the compounds commonly used to treat hypertension diminish the body’s capacity to absorb and retain magnesium and not the low level of magnesium.

IMO E is the correct answer.

abhishekdadarwal2009 · Answer

Researcher: Hard water contains more calcium and magnesium than soft water contains. Thus, those who drink mostly soft water incur an increased risk of heart disease, stroke, and hypertension, for people being treated for these conditions tend to have lower levels of magnesium in their blood.

Which one of the following, if true, most undermines the researcher’s argument?

(A) Magnesium deficiency is not uncommon, even in relatively prosperous countries with an otherwise generally adequate diet. 
whether the deficiency is common or not is not discussed, and is also out of scope.

(B) Magnesium is needed to prevent sodium from increasing blood pressure. 
Good finding through the scientific research ,but it has nothing to do with our argument,clearly out of scope.

(C) As people age, their ability to metabolize magnesium deteriorates. 
Sounds like a weakener but not a good one because we don't know about what age constitutes our case. so only age cannot be the deciding factor.

(D) The ingestion of magnesium supplements inhibits the effectiveness of many medicines used to treat high blood pressure and heart disease. 
Good!!,but who is talking out suppliments… Also we see that the weaken choices have to be taken as true always.but this choice goes too far from the main argument and only addresses isolated cases of when suppliments are taken.

(E) Compounds commonly used to treat hypertension and heart disease diminish the body’s capacity to absorb and retain magnesium.  
Best weakner,because it reverses the causality and leads to break the conclusion but stating that the compounds taken to treat such diseases cause the lowering of the magnesium.

VerbalBot · Answer

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Researcher: Hard water contains more calcium and magnesium than soft

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