LSAT 23 | Section 3 | Logical Reasoning: Q19

LR Question 19 Explanation

QUESTION TEXT: When a stone is trimmed by a mason and exposed to the…

QUESTION TYPE: Weaken

CONCLUSION: The monument was built much earlier than 1492.

REASONING: Rock varnish forms shortly after stone is cut. 1,000 year old material was found under the rock varnish.

ANALYSIS: This sounds like a good argument. But the correct answer reminds us of an obvious possibility: perhaps the monument was built with stones taken from another, older monument.

In Europe, many roman buildings were disassembled to build new buildings during the middle ages. The stones are older than the buildings.

___________

1. So? The 1,000 year old organic matter was found under the rock varnish.
2. CORRECT. This tells us that the stones might be much older than the monument. The monument could have been built in 1753, using 1,000 year old stones.
3. Who cares? Egyptian pyramids remind of of Mayan pyramids, but there’s no known links between them. This tells us nothing about how old the monument is.
4. So? Many buildings existed for a long time before anyone bothers to write something about them. The monument could still be quite old.
5. Was the monument built in a dry, sheltered place? Most monuments aren’t. In any case, the slower the rock varnish formed, the older the monument is. The organic matter dates from when the varnish formed.

Recap: The question begins with “When a stone is trimmed by a mason and exposed to the”. It is a Weaken question. Learn how to master LSAT Weaken questions on the LSAT Logical Reasoning question types page.