Question

Which of the following statements is the contrapositive of the given statement?

If dogs have fleas, they scratch all night.
If they scratch all night, then dogs have fleas.
If they don't scratch all night, then dogs don't have fleas.
If dogs don't have fleas, then they don't scratch all night.

Answer 1

The contrapositive of the statement "if p then q" is "if not q then not p."
Having this in mind, the opposite of the statement "If dogs have fleas, they scratch all night" is the third option - If they don't scratch all night, then dogs don't have fleas.