Why is the actual volume of lecture material on Coursera many times less than the declared one?

Question

IT education

Take, for example, a course in Chemistry .

Course at a Glance
10 weeks of study
10-12 hours/week

Accordingly, 10 * 10 = 100 hours in total
Now look at the list of lectures there - 7 units, each consists of a large set of mini-lectures. Why is the total amount of lectures not written on the course? After all, the volume of the material is one of the main parameters!
I wrote a Java program that sums up all the mini-lectures and calculates the real amount. She counted 17 hours! This is 5 times less than stated. Why is that? Maybe somewhere there are hidden course parameters where it is written?

Answer 1

This is not the amount of lecture material, but the estimated workload per week, that is, how much time you will spend studying the material and completing assignments
. For example, https://learner.coursera.help/hc/en-us/community/p. ..

Answer 2

You can talk about the load, etc.
But the point is that it's free. This greatly affects the quality of the material, and the volume, and home clocks.

Answer 3

maybe you mean the academic hour ?

Answer 4

1) With the proper approach, each of these 7 units can be read for 100 hours. So what you wrote there for the program and what you counted is not clear.
2) Did you take into account the time of practical classes and exams? Time for self-education and homework?