On this November page the dates are blank, but the month is known to contain five Fridays and five Saturdays. On which day of the week does the next month begin?

November has 30 days = 4 weeks + 2 days, so the two days that occur five times are the first two days of the month: it starts on Friday. 30 days later, 1 December is Friday + 2 = Sunday. (Saturday is the last day of November.)