Question

Give four examples of implications and for each write down their contrapositive. Have two be real world examples and two be math examples.

Answer 1

Real world

1. If it rains then I will stay indoors. The contrapositive is, if I will not stay indoors then it does not rain.

2. If I pass my examination then I will proceed to the next class. The contrapositive is, if I do not proceed to the next class then I did not pass my examination.

Math examples

P and Q are statements

1. P$\implies$ Q

Contrapositive : $\neg Q\implies\neg P$

2. If n is even then 2n is even. The contrapositive is, if 2n is not even, then n is not even.