Final answer:
The passage is informal due to colloquial language, a first-person point of view, and incomplete sentences that mimic casual conversational speech patterns.
Step-by-step explanation:
The passage displays an informal tone through the use of colloquial language, first-person point of view, and incomplete sentences. Phrases like "Who's giving it?" and "Let me know the details." are examples of colloquial language that make the text sound conversational as if spoken by a real person rather than written in a formal context. The use of the first-person point of view with pronouns such as 'I' and 'we' establishes a personal connection with the reader, contributing to the informality. Additionally, the text's incomplete sentences, such as "But we should be back in time for the fun" reflect the way people often speak in casual conversation, which is not always grammatically perfect but conveys the message in a relaxed manner.