Identify what you can properly conclude from the given premises: P: D → not AP: X–some–AC: ?

rkschisler July 26, 2016

example

Could you give an example in word form of what these premises would look like as sentences?

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Mehran August 8, 2016

@rkschisler of course! Here you go:

Some bridges built from 1950 to 1960 were built according to faulty engineering design.

B-some-FED

No suspension bridges are among the bridges that were built according to faulty engineering design.

SB ==> not FED

These examples are taken from Question 10 in Logical Reasoning I on the October 1997 LSAT.

Hope this helps! Please let us know if you have any other questions.

rkschisler August 9, 2016

Thank you!

TashaPenwell February 19, 2017

So "some" is a keyword in the question and if used the the variables (B, not FED in this example) shouldn't be negated?

Mehran February 20, 2017

@TashaPenwell not sure I am understanding your question here.

If you are asking if "some" statements have contrapositives like sufficient and necessary statements, the answer is no they do not.

Hope this helps! For a more in-depth discussion of these concepts, please watch our videos on Sufficient & Necessary and Quantifiers.

marinamyousef December 27, 2017

Would the conclusion be B-some-FED - > not SB?

Mehran January 9, 2018

Yes, you could combine as follows:

B-some-FED ==> not SB

To conclude:

B-some-not SB
not SB-some-B

Hope that helps! Please let us know if you have any other questions.