Page 79 - qrps

© 2014 Pacific Crest 79
2.2 Logical Reasoning
How can Tom determine what each box contains, by taking only one piece of fruit from one box?
Solution:
Tom takes a piece of fruit from the box with the label APPLES & PEARS. If the fruit he pulls
out is an apple, then the label APPLES belongs to this box. The box that said APPLES, then of
course should not be labeled APPLES & PEARS, because that would mean that the box with
Pears would have been labeled correctly, and this is contradictory to the statement given that
“none of the labels is on the correct box.” The label PEARS then belongs on the box incorrectly
labeled APPLES. If Tom had chosen a pear instead of an apple, the reasoning would have been
similar.
APPLES
APPLES
&
PEARS
PEARS
Critical Thinking Questions Developing your understanding
1. What are 10 types of logical fallacies?
2. What justifies that a step is correct?
3. What happens when you find a counter (or contrary) example when you’re working to prove that
something is true?
4. What are examples of conditions where a rule doesn’t apply or work?