[Q] Given the sentence "A group of young monks are holding a ceremony for passengers on boats." is it true that "A group of monks are in a ceremony."?
[A] A group of young monks falls under a group of monks category and holding a ceremony means they are in a ceremony.
The answer is yes.

[Q] Premise: "A man is scratching his head at a meeting while a person spoke."
Hypothesis: "A person speaks at a meeting."
Do we know that the hypothesis entailed by the premise?
[A] A person speaks at a meeting because another man is listening and scratching his head;.
The answer is yes.

[Q] Premise: "A woman in a brown coat and white scarf is walking on a sidewalk."
Hypothesis: "A woman is not wearing any winter clothing."
Do we know that the hypothesis entailed by the premise?

[A] One cannot be in a brown coat and white scarf and not wearing any winter clothing simultaneously.
The answer is no.