SAT Math type quest- CONVERSE RULE???

Test Preparation
1

<p>What is that rule where it's like... if x is true, then y is true... if x is not true, then y is true, etc.? (what i just said, didn't make any sense... i was just trying to give an idea)</p>

<p>In the SAT they always have one question where it's the statement like...Everyone in the swimming team is in the math team but not everyone in the math team is in the swimming team, etc... Which of following cannot be true? </p>

<p>Can someone give the general math rules that we can apply to see which statemnet isn't true? Can someone give me actual examples (preferrably moderate to difficult ones) that's similar to the ones on the sat???</p>

2

<p>The converse is not always true, but the contrapositive is, e.g. x → y implies ~y → ~x. These questions don’t appear very often on the SAT, but be prepared to see them. For example,</p>

<ol>
<li>If it rains, then I bring an umbrella. Which of the following must be true?</li>
</ol>

<p>A. If it doesn’t rain, then I don’t bring an umbrella.
B. If I bring an umbrella, it is raining.
C. If I don’t bring an umbrella, it is not raining.
D. If I don’t bring an umbrella, it is raining.
E. None of the above</p>