According to the rules of the Room Service in the hotels the guests can order breakfast from 6 am to ... am

Ответ (EN)

The missing part of the sentence is the end time for ordering breakfast. Based on typical hotel service hours, a common end time would be 10 or 11 am. Since the sentence structure implies a specific time, a plausible answer is '10'.

The completed sentence: According to the rules of the Room Service in the hotels the guests can order breakfast from 6 am to 10 am.

Перевод (RU)

Согласно правилам обслуживания номеров в отелях гости могут заказать завтрак с 6 утра до 10 утра.