I've heard it's so parents can get the kids to school at 0800 and then start job a 0900. But why school is out at 1500 and job at 1700 is a mystery.
School ends at 3pm so that the teachers, who work a 9-5 like you, get two hours after class to grade homework and prepare lessons for the next school day.
"But why school is out at 1500 and job at 1700 is a mystery."
Same here. And I've never figured out why DST fades the curtains.
It also improves the rush hours by enlarging the time range. Most jobs start at 9am or later, so if kids also started at 9am or later the morning rush hour (for traffic but also public transportation) would be even worse.