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 quick answer by Art M)

Actually statements 2 and 3 are true and the others false.

FOR s1 = -1 TO 0
FOR s2 = -1 TO 0
FOR s3 = -1 TO 0
FOR s4 = -1 TO 0
 t = (s2 = 0 AND s3 = 0 OR s2 AND s4)
 IF t = s1 THEN
    t = (s1 = 0 AND s3 OR s3 = 0 AND s4)
    IF t = s2 THEN
      t = ((s2 = 0) = (s1 OR s4))
      IF t = s3 THEN
        t = (s1 = 0 AND s2 = 0 OR s3 AND s4)
        IF t = s4 THEN
           PRINT s1; s2; s3; s4
        END IF
      END IF
    END IF
 END IF
NEXT
NEXT
NEXT
NEXT

lists

0 -1 -1 0

these being the codes for false, true, true and false.

If only 1 were true then 3 would be true also--a contradiction.

Posted by Charlie on 2007-05-16 18:59:10