501: Learning time

Read this post on lost learning time.

Here's his basic point:

... roughly 10 of 60 minutes are not spent learning. 
In one day, roughly 50 minutes.
In a 5 day week, 250 minutes.

In a typical school year, 8,700 minutes not utilized for learning.

Now, let's be realistic and cut that number in half because we all know there are assemblies and other events that cut into learning time throughout the school year. That leaves us with 4,350 minutes of time not spent learning.

1. Do you agree with his analysis?
2. How about his calculations?
3. What should be done?