At Southgate Mall, mattresses are sold only at Mattress Madness. Every mattress at Mattress Madness is on sale at a 2...

Julie on August 6, 2019

Diagramming (B)

Hi LSAT Max, How would you diagram the first sentence in choice (B)- Diana's refrigerator, and all the food in it, is in her apartment? would refrigerator and food both be separate sufficient conditions that lead to apartment, the necessary condition they have in common? That was my thought process, which is why I eliminated it. Many thanks for the help!

1 Reply

Irina on August 6, 2019


This parallel reasoning question is best approached by looking for a similar pattern of reasoning rather than using conditional diagrams. I think the overall argument here is best characterized as a categorical syllogism, and the statement "Diana's refrigerator and all the food in it" is not a conditional statement.

The argument tells us:

Every A at B are at C.
Every mattress at the mall is at Mattress Madness.

Every A at C is D.
Every mattress at MM is on sale.

Therefore, every A at B is D.
Every mattress at the mall is on sale.

Let's compare it to (B):

food= mattress, apartment = mall, refrigerator = MM store, bought last week = sale

All A at C are at B
All A at C are D
Therefore, all A at B are D.

This is clearly a different pattern of reasoning, thus allowing us to eliminate (B).

I know it is tempting to try to convert every statement to a conditional, but it is neither necessary nor useful for an argument that does not follow a conditional formal:

P ->Q
Therefore, Q

Does this help?

Let me know if you have any further questions.