Worksheet 2 – Answers
MATH 228-03: Discrete Mathematics
Fall 2024
Wesleyan University
Deductions!
The exercise below is intended to give you practice making logical deductions.
The following arguments are attempts at deductive reasoning. In each one, the statements
above the horizontal line are the hypotheses and the statement below it is the conclusion. For each
argument, decide whether the reasoning is correct or incorrect; in other words, decide whether the
conclusion can be logically inferred from the hypotheses. Try to justify your answers.
1. (a)
If wishes are horses, then pigs can fly.
Wishes are horses.
Pigs can fly.
(b)
If wishes are horses, then pigs can fly.
Wishes aren’t horses.
Pigs can’t fly.
(c)
If wishes are horses, then pigs can fly.
Pigs can fly.
Wishes are horses.
(d)
If wishes are horses, then pigs can fly.
Pigs can’t fly.
Wishes aren’t horses.
Answer. The reasoning in each of the following is correct, and only these: (a), (d).
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