#23 - Global, Rule Substitution

[salman]

Can you draw the conditional statement for answer C and not the contrapositive. I am having a hard time following the jump straight to the contrapositive.

This is the conditional statement I have
F/t and M/t ---------) Kt

Shouldn't the contra be
K/t -------) Ft or Mt

[Rachael Wilkenfeld]

Hi salman

For answer choice (C), I would draw the conditional as a block.

I would put FMt in a block for the sufficient and Kt as the necessary condition.

For the contrapositive, I would write Kt FMt in a block.

It looks like for your conditionals, there are a few issues. First, you didn't negate the sufficient condition in the unless equation. Second, the original statement should indicate that if either F or M is not in T, then K has to be in T. Your conditional says that if they both ARE in T, then K must be in T.

Hope that helps!

[salman]

Thank you !

[jimmy1115]

Hi,

want to clarify a few unless statements applying to multiple sufficient conditions statement.

'A and B unless C' : not A or not B ---> C
'A or B unless C': not A and not B---> C

are these correct?

using the unless equation, when negating the sufficient conditions, the 'or' and 'and' both have to be logically negated as well right, 'or' becomes 'and' while 'and' becomes 'or'

thank you

[Hanin Abu Amara]

Hi Jimmy,

so Unless is a necessary indicator that's unique. You follow two steps here:

step 1: everything unless refers to gets diagrammed as you see it.
step 2: the sufficient condition is negated.

so you're correct. If a phrase was A and B unless C we have no A or no B --->

The and/or have to be switched when negated.

Hope that helps.