[nihil75]

Yea, it's meant to be a waste of your time.

More accurately, if you need to learn new things to complete it - it will be very time consuming.

Someone experienced, or that uses relevant tech/skills on a daily basis should complete it in less than the time allotted.

Therefore "homework" coding challenges are useful for discerning if a candidate has relevant, current experience.

See the article on college professor solving a 30+ of CS problems in one day.

Whiteboard challenges, on the other hand, evaluate a candidates thinking process & presentation skills.

Whiteboard challenges