GRE Subject Test: Math : Real Analysis
Study concepts, example questions & explanations for GRE Subject Test: Math
All GRE Subject Test: Math Resources
Example Questions
Example Question #146 : Other Topics
Using DeMorgan's law, is the statement 
No, the equivalent statement is
No, the equivalent statement is
Yes, the statements are equivalent
No, the equivalent statement is
No, the equivalent statement is
No, the equivalent statement is
The easiest way to remember DeMorgan's law is that you flip the symbol upside down (which changes union to intersection and vice versa), complement both sets (remembering that the complement of a complement is just that set), and either remove parentheses or add parentheses and place the complement symbol outside of it.
Flip the union symbol to an intersection symbol, complement both sets, and remove the parentheses.
Example Question #1 : Logical Equivalence
Suppose A, B, and C are statements such that C is false if exactly one of A or B is true. If C is true, which of the following is also true?
Both A and B are True
A is false, B is true
A is true, B is false
Both A and B are both False
Both A and B are both False
Step 1: Let's break down the logic problem...
C is false if A or B is True.
Example: C-False, A-True, B-False.
Step 2: Try to find what happens if C is true
If C is true, "or" changes to "and", and True becomes false..
So: C-True, A-False, B-False..
A and B must both be false for C to be true..
Answer: Both A and B are False.
All GRE Subject Test: Math Resources
