So i friend of mine boosted me through the quest The Amphitheater of Anquish (The Champion of Anguish - Quest - World of Warcraft)
And it got me thinking. From the last boss i got 16k xp with rested and hairloom items and killing it with boost took me about 1 min so thats 16k xp for 1 min 10min = 160000 and in 1h u got about 960000.
So thats about 1.5h. So heres the thing when u kill the last boss abond the quest and re take it kill boss again do so over and over and over again.
U can either have a really good friend helping you or boost yourselfe with 2 accs