Question

Determine if the argument is valid or invalid. Give a reason to justify answer.

If it is cold, then you need a coat.
You do not need a coat.
∴ It is not cold.

Answer 1

invalid

Answer 2

It's actually valid.

Answer 3

valid

Answer 4

oh

Answer 5

TYPO lol
if p then q
not q
therefore not p

THIS is the valid one, sorry

Answer 6

Modus Tollens*

Answer 7

thanks Guys :)

Answer 8

yep

Answer 9

okay, first, we start with
p --> q
and
~q

right?

Answer 10

yeah

Answer 11

Well, what does it mean if
p implies q?

It means either p is false, or q is true, right?
Because if p is not false, or p is true, it automatically implies q is true.

Answer 12

yeah

Answer 13

So p is false or q is true.
At least one of these must be true, right?

Answer 14

But you also have the assumption
q is false
(You do not need a coat)

Answer 15

yep

Answer 16

p is false OR q is true.

At lease one of these statements is true, and it's NOT the second statement, because we assumed q is false.

Then it must be the case that the first statement is true (p is false)
or (It is not cold)

Answer 17

ty Zug <3

Answer 18

anytime