Question

if it is 12:00 noon, then the sun is shining . find the counter example

Answer 1

What we have here is a statement with two parts. We have a fact (It's 12 noon) and a conclusion. (The sun is shining.)

We know that if it's 12 noon, the sun has to be shining. This is a logical inevitability. So, our counter-example would be if the sun WASN'T shining. What could we conclude then?

If the sun is NOT shining, it is NOT 12 noon.

If it's 12 noon, the sun must be shining. Therefore, if the sun isn't shining, it can't possibly be 12 noon!

Your other question can be solved in the same way.