Find the true and the false statements.
1. Either 2 and 3 are both false or 2 and 4 are both true.
2. Either 1 is false and 3 is true or 3 is false and 4 is true.
3. If and only if 2 is false, then either 1 or 4 is true.
4. Either 1 and 2 are both false or 3 and 4 are both true.
(In reply to
re: Boolean by Dej Mar)
Under the supposition that 1 is true and the rest false:
(A) "either 1 or 4 is true" is true
(B) "2 is false" is true
Stating that "if and only if (B) then (A)" is then true, as both are true. But the supposition was that this statement (3) is false. The supposition is contradicted.

Posted by Charlie
on 20070517 12:18:34 