Discussion
If the "fishologist's" statements are true, which of the following can be concluded?
*This question is included in Exercise Set 4: Intro to Connectives, question #7
| (A) | If the strange-looking creature does not swim in the sea, it must walk on land. |
| (B) | ... |
| (C) | ... |
| (D) | ... |
| (E) | ... |
| (F) | ... |
The solution is
Posted: 05/30/2011 16:44
Why couldn't he swim in both?
Posted: 05/31/2011 02:22
If he swims in both freshwater and saltwater, then the statement "he swims in freshwater" is true.
However, the correct answer choice says "if he does NOT swim in the sea, then he must swim in freshwater". If he does not swim in the sea, then he can't swim in both the sea and freshwater.
Symbolically:
C → F
F → SS or SFW
So if you have C and ~SS, you must have SFW.
However, the correct answer choice says "if he does NOT swim in the sea, then he must swim in freshwater". If he does not swim in the sea, then he can't swim in both the sea and freshwater.
Symbolically:
C → F
F → SS or SFW
So if you have C and ~SS, you must have SFW.