Is it true that a teacher would tell child yes but if another ask the same question say no?

No, that's not generally true. A good teacher should strive for consistency and fairness. While a teacher might answer a question differently depending on the context (e.g., a follow-up question clarifying the first one), they shouldn't give contradictory answers to the same question simply because different children asked it. That would be confusing and unfair to the students.