LSAT 4 | Section 4 | Logical Reasoning: Q21

LR Question 21 Explanation

QUESTION TEXT: During construction of the Quebec Bridge in 1907…

QUESTION TYPE: Must be True

FACTS: The cantilever of a bridge under construction in Quebec City collapsed in 1907. Bridge construction became safer after the Quebec City bridge collapse. Engineers began to use more rigorous mathematical analysis rather than rules of thumb.

ANALYSIS: After reading this once, I wasn’t sure what to conclude. This sort of question simply depends on keeping the details in mind. The central fact is that bridge construction got safer after 1907 by using better math.

___________

1. Since thousands of bridges had been built using the old methods, it’s highly implausible that they were all unsafe. Engineers would have noticed if all of the bridges were collapsing.
2. Hard to say. He might have prevented it, but perhaps he wouldn’t have even heard about the trouble if he had been on site.
3. We don’t know why earlier engineers didn’t use analytical methods.
4. Not true. If Cooper could have telegraphed a bit quicker, that might have saved the bridge even without the use of math.
5. CORRECT. This must be true. The rules of thumb were not sufficiently mathematical to save the Quebec bridge. Other bridges may also have been unsafe as a result.

Recap: The question begins with “During construction of the Quebec Bridge in 1907”. It is a Must be True question. Learn how to master LSAT MBT questions on the LSAT Logical Reasoning question types page.