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Exam time is coming and i'm review, he let us see the answer key to a sample exam but i'm still not sure how they came up with the following:

If the variables a and b range over the set of postive integers, then is each of the following statments true or false, circle ur answers.

http://suprfile.com/src/1/3p2it9s/lastscan.jpg [Broken]

1. For all a there exsits a b such that a < b. yes i see this is true,

2. For all b there exists an a such that a < b. But i'm confused on why this isn't true...or is it false based on the answer above, if for all a there exists b such that a < b?

3. There exists an a for all b such that a < b, I think i see why this is false, its a strong statement to say. if a = 5 b = 5, then this is false

4. There exists an a for all b such that a <= b, this is true becuase if u let a = b, then its always true.

5. There exists a b for all a such that a <= b, i don't see why this is also not true though.

Can someone explain to me why they are true and why they are false exactly?

Thanks!

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# Homework Help: Reviewing for exam, confused on this universal/exists true/false

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