Question

If p∨q is true, then what must be true about the truth values of p and q?

Where p and q are statements, "p and q" is false if
p is false.
Which of the following statements is the contrapositive of "If I have money, then I spend it"?


If I don't have money, then I don't spend it.
If I spend money, then I have it.
If I don't spend money, then I don't have it.

Answer 1

If p V q is true also known as p or q it would relate to the Disjunction truth table. The values of p and q that equal true outcomes for p V q are: p = True - q = True equals True
p = True - q = false equals True
p = False - q = True equals True
However if there both false than the outcome is false.

p and q truth table also known as p ^ q is:
p = True and q = True equals True
but if either of these changes to false the equivalent is false.

So your second statement or question is correct.
Now a contrapositive is not only changing the locations of "p" and "q", but also negating them as well.

For example:

p = true and q = false
Contrapositive is:
q = true and p = false

Get it?

So your final question's answer would be:

C - If I don't spend money, then I don't have it.

Hope this helps, G'day.