A man in a shirt and tie speaks to a group as an older woman holding a cup of coffee looks on.
The man is wearing khakis.
Just because a man is wearing a shirt and tie doesn't necessarily mean that he has on khakis. The type of pants he is wearing can't be inferred.
A shirt and tie are not usually khakis.
Just because the man has on a shirt and tie does not mean he is wearing khakis.