Question

CaptchaIsExist    CaptchaIsValid   =   Result
--------------    -------------       --------
   true                false        =    false

   Any other variations             =    true

Now how to write logic for having these results ? It looks simple but i think not enough.

Answer 1

An alternative to @Binary Worrier’s solution:

bool Result = CaptchaIsValid OR NOT CaptchaIsExist

I think this expresses the logic more naturally, i.e. it conveys the intended logic when you read it.