Sufficient and Necessary Diagramming Drill #5 and #6

[jostomel]

I have a question on lesson 2 homework, pg 2-34 and 2-35. I am having trouble seeing the correct answer on questions 5 and 6. on 6 six it looks like Maria will speak if the chairman does NOT speak, but the diagram is Maria speaks then chairman doesn't speak. I think I am getting hung up on all of the negatives. same question on 5

[David Boyle]

I have a question on lesson 2 homework, pg 2-34 and 2-35. I am having trouble seeing the correct answer on questions 5 and 6. on 6 six it looks like Maria will speak if the chairman does NOT speak, but the diagram is Maria speaks then chairman doesn't speak. I think I am getting hung up on all of the negatives. same question on 5

Hello jostomel,

Yes, negatives can be tricky. But hang in there!

For "unless" and similar negative-leaning "necessary" indicators, you keep what's after the word, and negate what's before it. So, it does look like if M speaks, chairman doesn't. With what you say above, you switch around the "if".
I.e., it's

"If Maria speaks, the chairman doesn't"; but the way you put it above is,

"If chairman doesn't speak, Maria does." Which seems to be a Mistaken Reversal of sorts. Be careful where the "if" goes!

Hope this helps,
David