#14 - Archaeologist: An ancient stone building at our

[Capetowner]

Hi oq058420!

I can certainly address why answer choice (B) is correct. The numbers you provided in your hypotheticals seemed to make sense to me in skimming them and looking at the premises in the stimulus. One thing missing from your post was the variable of "occur[ring] naturally in the area," which seems to be key to why answer choice (B) is correct.

The conclusion is, "Therefore, the building we are studying probably was not a dwelling." How does the author arrive at this? The author notes that the building is made from 3 different types of stone, but only 1 of them is found naturally in the area. The author seems to make an inference that the presence of the other 2 types of stone indicates that it's not a dwelling, but if so, this isn't stated.

In addition to the numerical hypotheticals you suggested, you might also find it helpful to think of the middle two sentences of the stimulus in terms of a Venn diagram, or something similar--there'd be one encompassing circle for "buildings," one within it covering more than half for "dwellings," and the same amount for "limestone." Since they both cover more than half, those inner two circles overlap, i.e., we know that there are some dwellings are made from limestone.

Answer choice (B) states, "Most of the buildings at the site that were not dwellings were made, at least in part, from types of stone that do not occur naturally in the area." This connects the sentence about not being from the area to the conclusion. It makes sense to conclude from the types of stone it is made out of--which included stones not from the area--that this building is not a dwelling if, as (B) supposes, most non-dwellings utilized stones that were not from the area.

How is E not even spoken about. It says most from that time period are only Limestone. Surely E strengthens by increasing odds of the building being built with external resources, therefore strengthening the conclusion?

[Jeff Wren]

Hi Capetowner,

I believe that Adam's example using the numbers was just to explain how the formal logic works in the question, but I wouldn't recommend going through these numerical examples while solving the question during the test. For some students, thinking of about the issue using numbers can help make sense of the situation, but definitely not for everyone.

As for why Adam stated that "at least 5 of the former being only limestone," this is because in his example six buildings are made of only limestone, and since at least three of the 4 (i.e. most) non-dwellings in his example are made of multiple types of stone, that would leave at most one non-dwelling made of only limestone. That in turn would mean that at least 5 of the dwellings would be only limestone. In other words, either all 6 of the only limestone buildings are dwellings or 5 of the only limestone buildings are dwellings and 1 is a non-dwelling.

All that being said, you can solve this question without using these numerical examples, and if you don't find them helpful, you can disregard them.

As for your comment that "The formal logic way seems impossible to do in a minute and 30 seconds," please keep in mind two points. First, not every logical reasoning question will get solved in a minute and 30 seconds, that is simply an average. As with any average, there should be some LR questions that take less time (perhaps 1 minute) while others take longer (perhaps 2 minutes). Second, while many students find formal logic a difficult topic at first, this question can be solved in that amount of time with proper understanding of/practice with these concepts.

The simpler and easier way to approach this question is understanding that nothing in the premises tells us anything about buildings that are not dwellings, which is what is mentioned in the conclusion. To strengthen this argument, we really need an answer that connects non-dwelling buildings to multi-stone buildings (like the building mentioned in the conclusion), and only Answer B connects these.

Answer E (like the other wrong answers) is incorrect because it does not support the conclusion that the building is probably not a dwelling. What about this answer would suggest that the building is not a dwelling? Perhaps it was a dwelling, but was just special because it was the dwelling of the chief, religious leader, etc..