take to upgrade any computer. It's different for different computer and maybe the time of day you are doing it. But you could maybe save a little time by download and create you windows10.iso first. In fact, one download but make 2 .iso, one for you and one for your friend.
Friends right now i am using windows 8.1 and I want to upgrade windows 10 but it is taking so much time and I am looking for less time to spend on it so if anyone know anything about this please inform.