who know bitcoin will become in 2018 i think its not possible it become 50k USD 
That way too optimistic dude, 50K USD is a lot and thinking that we are only still at 2k+ USD range. That 50k USD price is too far and hard to get even close to, considering that we are only a months away from 2018. My guess is that we will be reaching 3k-3.8k USD at tops next year, but who knows? Let's just hope for the better for bitcoin in 2018, I mean, it is what we really want right?