Bitcoin to reach 20k USD in 2018 is very possible. We are already halfway there and a year is more than enough to see Bitcoin's value to increase at least twice. Perhaps Bitcoin could even reach the 30K dollar mark within 2018. That is also possible. I am not saying that it is possible because there are a lot of possibility in the future but I am telling that it is possible because of Bitcoin's history. Let's just take a look at Bitcoin's history this year. We started the year 2017 at the price of almost 1k USD, then it reached an ATH of 11k+ USD, so if we start at 10k in 2018, then 20k,30k, and 50k is highly possible.