how many minutes pass if I watch 10 videos of 3 to 4 minutes each?
( to be exact, from 1 to 10 from this playlist)
https://www.youtube.com/playlist?list=PL7rafPvkGvYQJdoYozNLEmgtUNYDVt0P4
10 x (3 -- 4 ) = 30 to 40 minutes
