"It would be very hard for a man to live with me unless he's terribly strong."– Coco Chanel

JasonBeers April 24, 2018

Not a=> b vs b=>not a

I don't understand the difference between not vh2l therefor TS, vs TS therefor not VH2L. It seems like if A is not B then B is not A

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Anita April 24, 2018

Sometimes, diagramming can create more confusion if you're not sure what the statement is saying, so let's translate these into regular sentences.

Prompt: If it's VH2L with me, then he must not be TS.
Now we find the match!

A: If it's not VH2L with me, then we must be TS. (Whoops, wrong way around.)
B: If it's VH2L with me, then he must not be TS. (It's a match!)
C: If he's TS, it must not be VH2L with me. (Flipped around. Maybe being TS is just one necessary part of making it not VH2L.)
D: If he's not TS, then it's not VH2L with me. (Hm, that actually would make it VH2L.)
E: If it's VH2L with me, then he's TS. (He may be TS, and it may still be VH2L, but it doesn't make sense here.)

Does putting it in words help?

commoner1024 June 27, 2018

According to the answer key, B is wrong although I assumed what we had to submit was a symbolic diagram of the situation.

Anita June 27, 2018

Hm, I may have been looking at the wrong thing when I wrote this - you're totally correct that A is right not B. Let me review and see what I did wrong. Apologies!

enkim91 June 21, 2019

Why was A the answer?

Victoria June 22, 2019

Hello! Thanks for your question.

The statement reads:
"It would be very hard for a man to live with me unless he's terribly strong."

There are two steps to follow when diagramming statements which include the word 'unless.'

Step 1: The word 'unless' introduces the necessary condition. The part of the sentence that follows 'unless' will be the necessary condition.

In this case, the necessary condition is: terribly strong (TS).

Step 2: Negate the other part of the sentence and make it the sufficient condition.

In this case, the sufficient condition is: very hard to live with me (VH2L).
But remember, we have to negate this!
So, the sufficient condition is: not very hard to live with me (not VH2L).

Therefore, the diagram would be:

Not VH2L - > TS

Making answer choice A the correct answer.

Addressing your initial question, A and B are not saying the same thing. While they are simply reversed versions of each other, they are saying two drastically different things.

A is saying:

If it is not very hard for a man to live with me then he must be terribly strong
OR
It would be very hard for a man to live with me unless he's terribly strong

B is saying:

If it is very hard for a man to live with me then he must not be terribly strong
OR
It would not be very hard for a man to live with me unless he's not terribly strong

Hope this is helpful! Please let us know if you have any further questions.