Case 1
- ¬A
Therefore
A→B
- The Padre beach is not poluted.
Therefore, if the Padre beach is poluted, it is good for surfing.
Case 2
- B
Therefore
A→B
- The Padre beach is good for surfing.
Therefore, if the Padre beach is poluted, it is good for surfing.
[.5in]
Case 3
-
A→B
C→¬B
C→A
C
Therefore
B∧¬B
- If it is a bird, then it can fly.
If it is penguin, then it cannot fly.
If it is penguin, then it is a bird.
It is a bird
Therefore, it cannot fly.