CR Question

[tim]

If I’m understanding your reasoning correctly, you are suggesting that A should be the answer because you think A strengthens the argument. I won’t repeat what I wrote to the previous poster, but your fatal flaw is that you are confusing an assumptions question with a strengthen question. If I have misinterpreted your line of reasoning, you are going to have to be more clear about what you are trying to say..

[ssajjan03]

I think I found the error in my reasoning..
assumption means: fill the gap between evidence and conclusion

when evidence says that the usage of pigment was stopped, it is immaterial as to why the usage was stopped. hence not A

If it were strengthen question, option A would have strengthened the premise " why abandoned pigment can not be used"

[tim]

yeah, you definitely want to pay close attention to the difference between strengthen questions and assumption questions; as you've seen, sometimes that makes all the difference..

[otavioveras]

Ok, Tim. So I'll revert the question:

Why would I assume that "Michelangelo did not work on the painting over the course of several years" if the argument leaves open the possibility that he could have started the painting in 1508 and finished it in the same year?

[tim]

Exactly. If we assume that he completed the work all in a single year, then 1508 is definitely one of the years this could have happened, which is entirely consistent with the argument. Assuming he did everything in a single year restricts the dates in such a way that the conclusion is sound. If on the other hand we allowed him to to work for several years, he could have started before 1507 and/or ended after 1509. This is why we need the assumption in order to be sure of the conclusion..

[chrisficalora]

Exactly. If we assume that he completed the work all in a single year, then 1508 is definitely one of the years this could have happened, which is entirely consistent with the argument. Assuming he did everything in a single year restricts the dates in such a way that the conclusion is sound. If on the other hand we allowed him to to work for several years, he could have started before 1507 and/or ended after 1509. This is why we need the assumption in order to be sure of the conclusion..

Tim - you are not assuming he completed the work in a single year, the conclusion is in fact stating Mich finished the painting in 1508.

Does anyone else think: A) this question is terribly inconsistent to what is actually on the GMAT? B) incorrect answer choice?

Conclusion - Mich completed the painting in 1508.
Premise 1 - Coin in painting wasn't minted until in 1507.
Premise 2 - Pigment in painting no longer used by Mich sometime during 1509.

What type of question? Assumption. Meaning, the conclusion MUST be true due to an unstated premise. If you negate this Assumption, the Conclusion ceases to be true.

The Manhattan answer is B: Mich did not work on the painting over the course of several years.

Let's first point out the difference between B and the conclusion. Conclusion states the painting must have been COMPLETED in 1508. Answer choice B states that the painting wasn't WORKED ON over the course of several years.

Let's negate answer choice B. The painting was worked on over the course of several years. Does this mean the painting wasn't completed in 1508? No it does not rule out that possibility.

As previously stated, the simple nature of assumptions/conclusions is that if you NEGATE the assumption, it will DESTROY (wipe-out, kill, terminate etc.) the conclusion. The conclusion is still very much in the working realm of possibilities when we negate Answer choice B.

Ex: In 1505 Mich started working on the painting and stopped, before going on vacation until 1507. He came back and started working on the painting again. While working on the painting in 1507/1508 he decided to add in this brand new coin recently minted. He completed the painting in 1508. The painting was worked on over the course of several years but was completed in 1508.

This proves the assumption can be negated and the conclusion still proven true.

OK now someone prove me wrong.

[jnelson0612]

Tim, Please tell me where is the fallacy in the reasoning below:

The conclusion of the argument is that Michelangelo must have completed the painting between 1507 and 1509.
why did he do so : Michelangelo is known to have abandoned when a cheaper alternative became available in that year.

Q find assumption:
Hence, if Michelangelo is not left with earlier stock of pigment after 2009, he will not use it otherwise he will use it (note the reason of abandonment i.e. cheaper option)

hence A
Choice B: over the course of several years can not just focus on 2009 and leave 2007 , just because it is an answer.
official explanation:
"In order to conclude that the painting must have been completed before 1509 on the basis of the pigment, we must assume that he did not begin the painting before 1509 using the old pigment and complete the painting after 1509 with the new pigment. "

this explanation seems to be derived from answer rather than the question itself..

appreciate if you can clarify

I'm sorry, but I've read your post through several times and I don't understand it. I'm particularly struggling with the following, but I'm not understanding some of the rest of your post.

"Hence, if Michelangelo is not left with earlier stock of pigment after 2009, he will not use it otherwise he will use it (note the reason of abandonment i.e. cheaper option)"

Will you please try to write out your question again? Make it as simple as possible so that we can follow. :-)

[JbhB682]

Following was my reason for thinking D was in the running

where am i going wrong ?


- The wooden panel on which the painting was executed cannot be tested accurately for age.

Shouldnt this be true ? if the panel could be tested for age, we would not say Michaelangelo painted this most likely between "1507 through 1509" ?

please let me know where am i going wrong here

[RonPurewal]

i'm sorry, but i don't understand what you are trying to ask.

are you asking about the specific phrasing?
if THAT is the question, then, these two wordings are interchangeable:
between 1507 and 1509
after 1507 but before 1509

"through" implies that he took that ENTIRE PERIOD to do the work, so, that's not something you would see here. (if someone says "I worked for the government from 1990 through 2003", that means she/he worked for the government for that ENTIRE period -- between 12 and 14 years, depending on the exact dates.)

if you're asking about something else, please clarify. thank you.

[JbhB682]

A newly discovered painting on wooden panel by Michelangelo must have been completed after 1507 but before 1509. It cannot have been painted earlier than 1507 because one of its central figures carries a coin that was not minted until that year. It cannot have been painted after 1509 because it contains a pigment that Michelangelo is known to have abandoned when a cheaper alternative became available in that year.

Which of the following is an assumption on which the argument depends?
- No stocks of the abandoned pigment existed after 1509.
- Michelangelo did not work on the painting over the course of several years.
- The coin depicted in the painting was known to general public in 1507.
- The wooden panel on which the painting was executed cannot be tested accurately for age.
- Michelangelo's painting style did not change between 1507 and 1509.
.

Hi - when one read's the blue font bit specifically, as a test taker -- i think there are two scenario's

a) the painting has BOTH original pigment and new cheaper pigment
b) the painting has ONLY original pigment

Can one assume, both scenario a and scenario b are possibilities ?

[esledge]

First I’ll note that the blue text is the conclusion of the given argument.

It sounds like you are saying “if [blue text=conclusion] is true, then you can further conclude either (a) or (b).” These seem like fair inferences to me, but this is not a Draw a Conclusion question, so I think you are either approaching this backwards or wasting time answering a different question.

On Assumption questions, the logical order is “We need [correct choice] to be true in order to conclude [blue text=conclusion].”

It can be useful to do a Negation Test of the correct answer to confirm: “If [correct choice] is NOT true, even partially, the [blue text=conclusion] CAN’T be true.”

Do you see how correct answer (B) fits this model?

[JbhB682]

Hi Emily - thank you for responding. I was between B and E and I negated both.

Negation should make reaching the final conclusion IMPOSSIBLE per my understanding. Link to my understanding was this Manhattan Blog post

https://www.manhattanprep.com/gmat/blog/simple-strategy-gmat-find-the-assumption-problems/

Negating B, I don't see how it COMPLETELY (100 %) destroys the conclusion in every plausible scenario.

In one scenario, I can see how the painting was completed in 1510 for example but in another scenario, i can still see plausible that the painting was still completed in 1508.

Negated B -- Michelangelo DID paint over several years.

If he painted over several years, he could have begun this painting in 1505 and finished in 1508 (he painted the 1507 minted coin in 1508)

It's still quite possible to reach the conclusion reached by the author

Hence I thought, given negated B does not a 100 % weaken the conclusion in ALL scenarios (once i negated), it cannot be a necessary assumption.

Thoughts ?

[esledge]

Negating B, I don't see how it COMPLETELY (100 %) destroys the conclusion in every plausible scenario.

In one scenario, I can see how the painting was completed in 1510 for example but in another scenario, i can still see plausible that the painting was still completed in 1508.

Negated B -- Michelangelo DID paint over several years.

If he painted over several years, he could have begun this painting in 1505 and finished in 1508 (he painted the 1507 minted coin in 1508)

It's still quite possible to reach the conclusion reached by the author

Hence I thought, given negated B does not a 100 % weaken the conclusion in ALL scenarios (once i negated), it cannot be a necessary assumption.

Thoughts ?

You are right that negating the correct answer should kill the conclusion. And you are right that negating (B) allows two scenarios, one of which kills the conclusion, and the other that doesn't.

Your mistake is putting these ideas together in an unnecessarily strict way: that ALL of the scenarios you get from negating (B) must ALL individually kill the conclusion. Nope! The existence of any one conclusion-killing scenario is all you need.

In one scenario, I can see how the painting was completed in 1510 for example

This possibility alone (it does not have to be a certainty) kills the word "cannot" in the conclusion.

[JbhB682]

Hi Emily - thank for your response ..

Just one follow-up on option B

The month in 1507 when the coin was introduced is not given ...so I think as a test taker, we can assume the coin was minted in any month in 1507

Let assume, the coin was minted in the summer of 1507 - June 1st 1507 was when the coin was minted

If so, here is a scenario when Michelangelo finished his painting before Jan 1st 1508

Plausible scenario #1 : Michelangelo started his painting on Nov 1st 1506 ...and finished his painting after one year on Nov 1st 1507... The painting has the minted coin because the minted coin was released 3 months earlier in June 1st 1507 ....

Plausible scenario #2 : Michelangelo started his painting on Jan 1st 1507 ...and finished his painting in 9 months itself on Nov 1st 1507... The painting has the minted coin because the minted coin was released 3 months earlier in June 1st 1507 ....

Both of these scenario's are scenarios' where the painting was made in one year or less and both these scenario's show -- that the conclusion (that the painting was done between Jan 1st 1508 and Dec 31st 1508) is not true

Thoughts ?

[esledge]

I think you are attempting a non-negation test (which isn’t a thing). You are taking as-is (B) and arguing that it CAN kill the conclusion.
The negation test is the opposite: You should take the opposite of (B) and show that not-(B) DOES kill the conclusion, thus proving that (B) is needed as-is.

Your reasoning:
In your two scenarios, you are assuming that (B) is true as stated: M did NOT work on the painting over several years. What does this do to the conclusion that the “painting…must have been completed after 1507 but before 1509”? The conclusion is still mostly true (the painting was complete before 1509, and after whenever the coin was minted in 1507…just maybe not after the very last day of 1507).

The fact is, (B) as written allows the conclusion to stand. Your scenarios suggest that some exceptions could exist, and the conclusion could be false...but under other possible (B) scenarios, the conclusion could be true.

The Negation Test:
But if you do negate (B) —if M actually did work on the painting for several years—then there simply is no “several years” period that fits between “after 1507 but before 1509,” and the conclusion can only be false. This is what confirms that (B), before negation, is “an assumption on which the argument depends.”