The quality of unrefined olive oil is not actually defined

Question

The quality of unrefined olive oil is not actually defined in terms of acidity, yet extensive tests have shown that the less free oleic acid an unrefined olive oil contains per liter, the higher its quality. The proportion of free oleic acid that an olive oil contains is an accurate measure of the oil’s acidity.

If the statements above are all true, which of the following conclusions is best supported by them?

A. When an olive oil is refined, the concentration of oleic acid in the oil is reduced.
B. The quality of an unrefined olive oil can be determined only by accurately measuring its acidity.
C. If an unrefined olive oil is intermediate in acidity between two other unrefined olive oils, it will also be intermediate between them in quality.
D. Free oleic acid is the only acid that unrefined olive oil contains.
E. People who judge the quality of unrefined olive oils actually judge those oils by their acidity, which the judges can taste.

LogicGuru1 · Accepted Answer

The quality of unrefined olive oil is not actually defined in terms of acidity, yet extensive tests have shown that the less free oleic acid an unrefined olive oil contains per liter, the higher its quality. The proportion of free oleic acid that an olive oil contains is an accurate measure of the oil’s acidity.

If the statements above are all true, which of the following conclusions is best supported by them?

Premise 1)  Olive oil's quality is not related to acidity  
 Premise 2) If amount of free Oelic acid is less in oil then quality is good
  The amount of free Oelic acid is inversely proportional to Oil's quality    
 Premise 3)  Amount of free Oelic acid is an accurate measure of oils ACIDITY

Mathematically speaking 
Amount of Oelic acid  ∝  Acidity {based on Premise 3}

Amount of Oelic acid  ∝  \frac{1}{Quality}  {based on Premise 2}

therefore :- Amount of Oelic acid  ∝  \frac{Acidity}{Quality}

Pre-thinking :- 
The  more free Oelic acid , the  more acidic  is the oil and  poor  is the quality.
The  less free Oelic acid  the  less acidic  is oil and  better  is the quality.

Extending the same logic a little bit more 
If some oil has  medium oelic acid  content, the acidity will be  moderate  and the quality will also be  medium .

What options matches our Pre-thinking.
C. If an unrefined olive oil is intermediate in acidity between two other unrefined olive oils, it will also be intermediate between them in quality.
 
    THE ANSWER IS C

A. When an olive oil is refined, the concentration of oleic acid in the oil is reduced.
B. The quality of an unrefined olive oil can be determined only by accurately measuring its acidity.
C. If an unrefined olive oil is intermediate in acidity between two other unrefined olive oils, it will also be intermediate between them in quality.
D. Free oleic acid is the only acid that unrefined olive oil contains.
E. People who judge the quality of unrefined olive oils actually judge those oils by their acidity, which the judges can taste.[

sayantanc2k · Answer

The acidity may INDICATE the quality, but it is not used to DEFINE the quality.

For example: Mass number of an atom is DEFINED as the total number of protons and neutrons in an atom. Higher the mass no., higher is the mass of the atom. Nonetheless mass is not used to DEFINE mass no. of an atom,but just an indication of the mass no.

Here, 
mass no. is equivalent to quality
mass is equivalent to acidity
no. of protons and neutrons is equivalent to some parameter that has not been specified in the passage -a parameter used to DEFINE the quality.

nevergiveup · Answer

Answer B and D seems extreme. Answer E seems out side of the scope. I am between A and C. I think I am going to chose C because the statement mentioned about unrefined oil not refined as mentioned in A.

So, C for me.

dwivedys · Answer

r0ckst4r · Answer

My problem with this is that C  directly  contradicts the first statement.

"the quality of unrefined olive oil is not actually defined in terms of acidity..."
Answer choice (C) says
"If an unrefined olive oil is intermediate in acidity between two other unrefined olive oils, it will also be intermediate between them in quality."
Which translates to intermediate in quality = intermediate in acidity
so quality = acidity
which contradicts the first part of stem.

Can someone help me understand this? Was this an official GMAT question?

FieryLeo · Answer

Hi Sayantac,

I was able to get down to C & E. 
I got highly distracted by the jump unrefined olive oil to olive oil in the last sentence.( do you think we should overlook this shift?)

The quality of unrefined olive oil is not actually defined in terms of acidity, 
yet extensive tests have shown that the less free oleic acid an unrefined olive oil contains per liter, the higher its quality.

Quality of unrefined olive is not a function of acidity : in mathematical terms
but - Lesser the oleic acid - higher the quality : some relation ship is there. (1)

The proportion of free oleic acid that an olive oil contains is an accurate measure of the oil’s acidity. 
Oleic acid is proportional to acidity :
higher the oleic acid - higher the acidity or 
lesser the oleic acid - lower the acidity. ( 2)

so combining 1 & 2 we can say that

lesser the oleic acid - lower the acidity - higher the quality

So why can't we say that quality is affected by acidity or acidity is a measure of quality : this is what E says.

E. People who judge the quality of unrefined olive oils actually judge those oils by their acidity, which the judges can taste.

Thanks in Anticipation

sayantanc2k · Answer

Of course you CAN say that acidity can be an indication of the quality - however you CANNOT say that the judges use that parameter to measure quality because nothing is said about the judges in the passage. So there is no way for you to conclude what method the judges adopt to measure the quality, whether they taste acidity or something else ( say, texture).

Hussain110 · Answer

Hi,
Can you tell me why choice D is wrong in this CR question. It is obvious from the last sentence that the measure of oleic acid is the only measure of acidity. This is directly stated in choice D. I think, to reject an option just because it is extreme can't be an intelligent method to solve CR Qs.

GMATNinja · Answer

First, the last sentence does not say that the measure of oleic acid is the ONLY measure of acidity. Instead, the last sentence tells us that it is AN accurate measure of acidity. There could be numerous other measures of acidity.

Second, just because the proportion of free oleic acid is an accurate measure of an olive oil’s acidity does not mean that free oleic acid is the ONLY acid in unrefined olive oil. Unrefined olive oil could contain numerous other acids, and that would not contradict anything in the passage.

Because of the word "only", choice (D) must be eliminated.

KarishmaChauhan · Answer

Hi Can you please help me explain why choice D is wrong? In passage it is mentioned that The proportion of free oelic acid in olive oil isAccuratemeasure of the Olive Oil acidity which means oelic acid is the only acid it contains because its proportion is the accurate measure of the acidity of the olive oil. Please help me where am I wrong here?

GMATNinja · Answer

Saying that "The proportion of free oleic acid that an olive oil contains is an accurate measure of the oil’s acidity" does not necessarily mean that free oleic acid is the ONLY acid present in the olive oil.

Here's an example: Let's say that the noise produced by screaming toddlers on a plane is an accurate measure of how crowded the plane is. That doesn't mean that there are ONLY screaming toddlers on the plane -- it just means that you can draw an accurate conclusion from one data point. If each screaming toddler is surrounded by a statistically average number of harassed parents, well-behaved siblings, and annoyed businesspeople, then the noise of the toddlers can be an accurate measure of the plane-crowdedness as a whole.

Similarly, the proportion of free oleic acid can be an accurate measure of the acidity of the oil, even if it is not the only kind of acid. Perhaps each drop of free oleic acid is accompanied by a fixed amount of other kinds of acid. In that case, free oleic acid is still an accurate measure even if there are other acids present in the oil.

I hope that helps!

Ilhomjon98 · Answer

Hi  IanStewart  
Could you please help with this question?

(C) is the best among other answer choice, but I have some doubt about it.

(B) is wrong because there would be other aspects of olive oil that determine the quality of olive oil.

Yet, If we use the same reasoning for (C), (C) cannot be supported from the passage. In other words, even if an unrefined olive oil is intermediate in acidity between two other unrefined olive oils, there would be other aspects that are better that those of other olive oils and that can determine the quality of olive oil.

Could you please explain how (C) is correct?

Thank you very much beforehand!

IanStewart · Answer

I wouldn't quite put it that way. B is contradicted by the passage -- it must be false. The first sentence in the passage tells us that the quality of olive oil is not defined in terms of acidity. So it must be assessed in some other way. So clearly there must be other ways, besides by measuring acidity, to judge the quality of olive oil.

Yes, using the 'same reasoning' for C won't work, because the reasoning wasn't correct. The question doesn't have anything to do with 'other aspects' that contribute to the quality of olive oil. It's only talking about how the quality of oil is measured. You might think of a different example: say in an elementary school, they don't use a ruler to compare the heights of the children (maybe they do it just by looking at the kids, or by standing them next to each other). But it turns out when you do use a ruler, the children the school judged to be tallest are actually tallest, and those judged to be shortest are actually shortest. The point is, we can measure height in different ways that lead to the same conclusions. The point is not that there are several factors that contribute to height that the ruler measurement ignores.

dato10kokli · Answer

So I correctly chose C) but I am not content with this answer.

The passage says that " less free oleic acid an unrefined olive oil contains per liter, the higher its quality"

based on that, answer choice C) says : "If an unrefined olive oil is intermediate in acidity between two other unrefined olive oils, it will also be intermediate between them in quality."

But thats not a guaranteed result, the passage says that the amount of oleic acid is negatively correlated with oil quality, its just one variable, lots of other variables can also deteriorate or icnrease its quality, for example fat % or etc.

So how C) can be correct answer? one unfiltered oil can have less oleic acid but more other substances that further deteriorate the quality, we are not told that the 3 sample oils are similar on any other aspect excepting oleic acids, nor we are told in the passage that oleic accids are the only variables that define oil quality.

Please help
 GMATNinja   VeritasKarishma

KarishmaB · Answer

I understand your concern but note that this is what we have:

"the less free oleic acid an unrefined olive oil contains per litre, the higher its quality"

This needs to hold, irrespective of other factors.

So if we know that oil B has less free oleic acid than oil A, we know Quality B > Quality A.
If we know that oil B has more free oleic acid than oil C, we know Quality B < Quality C.

Then Quality A < Quality B < Quality C

dato10kokli · Answer

Dear Karishma, I think the correct answer lacks the additional sentence “all other things equal”. Otherwise that inference is not warranted.

Its like saying the higher someone’s Gmat score is the better her chance of admittion in harvard, that does not warrant that among 3 people the one with average Gmat score holds the average chance of admission, cause there are lots of other variables, Gmat is just another positively correlated variable, In order to make inference about those 3 people we should know how they differ in Gmat and we should know that in all other instances they are equal

VeritasKarishma

GMATNinja

Can you please check my reasoning?

Posted from my mobile device

KarishmaB · Answer

If the premise given to you is "Higher someone's GMAT score, higher their probability of admission in Harvard," then that is what you have to take to be true, other factors notwithstanding.

Then if A has 740 and B has 710, then A's probability of admission is higher than B's (as per given premises). You do not need to add any condition here because you need to take your premises to be true. It doesn't matter even if in real life they may not always hold.
Whether the chances are average or not is not the point. It is about comparing chances of two people with different scores. If you are given that you can compare based on this factor alone, then you need to take it to be true.

mSKR · Answer

How to reject A?
A. When an olive oil is refined, the concentration of oleic acid in the oil is reduced.

1.  Is not A more like assumption in real scenario?  I mean when an unrefined oil is converted to refined oil, concentration of wanted components( such as oleic acid) would increase as unwanted components would be extracted.

We can reject A because:
 No relation  between acidity of refined and that of unrefined is given , so we  can not derive results about concentration  from the argument above.

please suggest  VeritasKarishma   IanStewart

IanStewart · Answer

The passage doesn't say anything at all about what happens to olive oil when it is refined. We want a conclusion that is "best supported" " by the statements above ", and if those statements don't even mention what happens when you refine oil, then they certainly don't support any conclusions about what happens when you refine oil. So A can't be right here.

The quality of unrefined olive oil is not actually defined

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The quality of unrefined olive oil is not actually defined

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