Two question from Master the Gmat CAT2004

mindfree

1. D
A-->B ==> Not B --> Not A. You can find the logic link in the first sentence.
If you are new to CR, you should start from the basics:
1. sufficient condition A-->B, then A is sufficient
2. Required condition A-->B, then B is required
3. If refers to sufficient
4. only if refers to required
5. unless, A unless B ==> A--> not B
etc.

2. B
I start by finding the conclusion and premises.

Conclusion: "New Evergreen Gum has twice as much flavor for your money as Spring"
Premises: "a stick of Evergreen Gum is twice as large as a stick of Spring Mint Gum, and the more gum, the more flavor."

A: wrong because the conclusion is about "one stick of gum", and has nothing to do with how many sticks in one package
B: right as more flavor in the gum negate the effects of size
C: there is no clear relationship between the weight of gum and the quantity of gum. Remember, we can only use "common sense" to make assumptions. In this question, the relationship is more technical and beyond common sense.
D: Cost is irrelevant as we are trying to dispute the conclusion, which is about flavor. So any other matter such as poisonous, risk to health, to pricy, too sweet, etc. habe NOTHING to do with the issue here.
E. Same as D.