Discrete Mathematics with Applications 4th Edition

Published by Cengage Learning
ISBN 10: 0-49539-132-8
ISBN 13: 978-0-49539-132-6

Chapter 2 - The Logic of Compound Statements - Exercise Set 2.3 - Page 61: 5


They did not telephone

Work Step by Step

If they were unsure of the address, then they would have telephoned ...(If p then q) They did not telephone ...(not q) ∴ They were sure* of the address. (not p) *read it as "not unsure" Modus Tollens: If p then q. Therefore not q implies not p
Update this answer!

You can help us out by revising, improving and updating this answer.

Update this answer

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.