Answer:
Not always true
Step-by-step explanation:
The statement given is
"If I am hungry, then I am not happy"
Hungry is the cause and not happy is the result.
But hungry need not be only cause for not happy. There may be other causes such as not having money, or time, or death of some relative, or any other ailment, etc.
Hence the converse need not be true always.
So "If I am not hungry, then I must be happy,"
can be true provided all other needs are satisfied
Hence need not always be true