I can get 99 cooking in 1 second.... starting from 98.
But botting 99 cooking from a low level is impossible in only 1 day. If we assume the avg xp/hr from 1-99 is 160k/hr, 13m xp divided by 160k/hr is about 81.25 hours.
3 days = 72 hours
But I could be wrong about 160k/hr, maybe it's more, maybe it's less.
Wine is the fastest xp possible I think, but 3 days you should be able to get it for sure.
Is it possible 24/7, I heard someone got it in 1 day

