The only way that bookstores can profitably sell books at below-market prices is to get the books at a discount from ...

Melody June 19, 2020

Timing

Hi, I'm struggling with timing for sufficient and necessary types of questions because of the need to diagram. I understood why each answer is wrong and why the correct answer is correct, but I am not able to get to the right answer in 1:30min. What do you recommend for timing issues? Thanks in advance!

Create a free account to read and take part in forum discussions.

Already have an account? log in

BenMingov June 19, 2020

Hi Melody, thanks for the question.

These questions are honestly quite time consuming if you haven't yet reached a high level of fluency translating from full sentences to diagrams. I would recommend setting aside some time to drill converting word sentences to conditional diagrams. Additionally, I would avoid writing the contrapositives for every single condition you notice; I would make the chain using the initial diagrams and then taking the contrapositive of the entire chain.

For example:

A -> B
B -> C
NOT D -> NOT C
NOT E -> NOT D

Here, instead of taking the contrapositive of all statements. I would take the contrapositive of only the last two.

A -> B
B -> C
C -> D
D -> E

This is combined to create: A -> B -> C -> D -> E and the contrapositive of the entire chain is

NOT E -> NOT D -> NOT C -> NOT B -> NOT A

This is a solid time saving strategy if you are comfortable enough with the conditions that you don't need to see each contrapositive.

I hope this helps. Please let me know if you have any other questions.