#10 - Cafeteria patron: The apples sold in this cafeteria

[David Boyle]

When i read this stimuli, Ithought the connection between "greasy" and "pesticide" had to be made for the conclusion.

I chose answer B believing that this supports the missing connection between two ceoncepts.

However the correct answer is A.

I dont understand why answer A must be assumed since washed apples does not support the conclusion that those apples are covered by pesticide.

Hello reop6780,

How was Thanksgiving?
Anyway, if they were washed, then they don't have pesticide anymore. So the assumption that they were NOT washed (which is what answer A says) at some point, is needed to assume that there could be a greasy pesticide residue left on the fruit. Try negating answer choice A--if they WERE washed, bye bye pesticide!
B may be a strengthener, showing that often, pesticide leaves a greasy residue. It's hardly a necessary assumption though.

Hope this helps,
David

[reop6780]

My thanksgiving was full of food after...food

Ah ha! I see what my problem was thanks to your explanation.

The way I read answer A was "the apples are not washed after harvest but WASHED before reaching the cafeteria." hence, even though negated, the answer A did not disprove the conclusion for me as the apples are washed anyway.

Thank you, David! Hopefully you had wonderful thanksgiving break as well regardless of students asking questions

[jostomel]

In Logical Reasoning Section 1 on this test, I am confused as to why question 10 is answer A not B. The reasoning in the stimulus says that the apples in the cafeteria are covered in pesticides, which makes them dangerous. And they got there by saying that the apples are sticky and that they are not washed by the cafeteria.
My prephrase was that the apples are sticky because of presticides which was answer B.
Why is this wrong?

[Nicholas Bruno]

Hi Jostomel,

I can see the confusion here! Let me reprint the answer choices to help you eliminate B and then we will talk about why A is correct.


(A) The apples that the cafeteria sells are not thoroughly washed after harvest but before reaching the cafeteria.
(B) Most pesticides that are sprayed on fruit before harvest leave a greasy residue on the fruit.

The reason B is incorrect is that it does not matter if *most* pesticides sprayed on fruit leave a greasy residue. All that matters is that the particular one used by the apple growers left a greasy residue. If 99 out of 100 pesticides did not leave a greasy residue but the apple growers used a pesticide that did, the argument would follow logically even though B would be factually incorrect. Thus, B cannot be an assumption.

A is correct because we know that the cafeteria does not wash the apples. However we know nothing about whether someone else washes the apples. I agree there is still an assumption that the pesticides are sticky but ONE of the assumptions is that no one else washed off the apple before it got to the cafeteria. Thus, A is correct.

Let me know if that helps!

[jostomel]

Yes that helps, I missed the "most" for the pesticides.

[Dave Killoran]

Hey Jostomel,

I see that Nicholas' excellent answer cleared things up for you, but I'm going to add some additional points for future readers looking for an explanation to this problem, and also because this is one of my favorite questions of all time.

As he pointed out, (B) is incorrect because of the word "most." The assumption there is actually "some," and if this answer read as "Some pesticides that are sprayed on fruit before harvest leave a greasy residue on the fruit," then it would be correct.

Answer choice (A) is actually a very neat answer in how it operates within the context of the argument. The argument itself can be seen in conditional terms, and the last portion would appear as follows:

• Premise: "Dangerous until it is washed" = D W
  
  Conclusion: "endangering its patrons" = dangerous = D

So, you have a conditional premise, and then a conclusion that is the negation of the sufficient condition. What assumption is needed? Well, the author is basically enacting a contrapositive, so you need the negation of the necessary condition, which would be "not washed" or W, Making the argument aprear as follows:

• Premise: "Dangerous until it is washed" = D W
  
  Assumption: Not Washed = W
  
  Conclusion: "endangering its patrons" = dangerous = D

Going into the answers, you can see that answer choice (A) is all about not being washed, so that matches what we need here.

Over 50+% of test takers choose answer choice (B), so you can see how easy it is to be attracted by that answer. But take some time to study this problem—it's a great question and it reveals a little bit about how they think and how they put these questions together, both in terms of what is the correct answer and how they attract you to incorrect answers.

Thanks!

[Mkendz]

Having a little trouble understanding why answer choice A is correct.

The Author's argument is that the cafeteria is selling pesticide covered fruit because ether are greasy (and the cafeteria does not wash them before they sell them). The stimulus indicates that "Most fruit is sprayed with dangerous pesticides before it is harvested, and is dangerous until it is washed".

Answer choice A is correct because the first part of the answer states that " the apples the the cafeteria sells are not throughly washed after harvest" this can also be proved by using the negation technique and then weakening the argument. However the second part of the answer is throwing me off "but before reaching the cafeteria" ?

Im assuming this means that the apples are washed before they are harvested and not after ? does this have the same meaning as if there was a comma in the answer " The apples that the cafeteria sells are not thoroughly washed after harvest but before, reaching the cafeteria ?
Idk it just doesn't make sense to me even if there were a comma it still isn't clear.

Just looking for an understanding, Thank you

[Lucas Moreau]

Hello, Mkendz,

You were correct for your first part of the analysis. Well done!

The second part is covering all possible gaps. We know the cafeteria is not washing the apples. (Also: Yuck! ) The conclusion that the apples are unwashed once sold can only be true if the apples are not washed before they reach the cafeteria.

If answer choice A wasn't true, then maybe a food distributor that gathers the apples after harvest might wash them there, thus getting rid of the pesticides and making the conclusion untrue. (Perhaps the apples are greasy because the cafeteria cooks greasy food and the grease gets on everything? )

So answer choice A being true ensures that the apples were never washed between harvest and being sold to customers, which means that the conclusion is valid.

Hope that helps,
Lucas Moreau

[laurat]

I also had issues with the usage of "but" in answer A. I understand why it's correct now but I don't feel confident that I wouldn't fall for something similar in the future, especially under time pressure. I hope this isn't too vague, but do you have any tips for reading more carefully/taking note of nuance? I look for indicator words and identify the conclusion but this just seemed to come out of left field.

[Kristina Moen]

Hi Laura,

Great question. The word "but" here just indicates the two ends of a time period. Think of the ends of string. "I took the train after breakfast but before lunch." Here, "breakfast" is one end of the string and "lunch" is on the other end. I took the train sometime between those ends. It can be helpful to make a note on your test when you see this again. You can write something like "Harvest |-------| Cafeteria" so you can clearly visualize the time period. Answer choice (A) is saying that the apples were NOT washed during that time. So with the Assumption Negation technique, you ask yourself "What would happen if the apples WERE harvested during that time?" Well, the pesticides would be washed off and the author's conclusion "Clearly, the cafeteria is selling pesticide covered fruit, thereby endangering its patrons" would be undermined.

Hope this helps. I like the way you're thinking - look at each question as an opportunity to learn skills and techniques you can apply on test day.