Doubling of the quoted amount is possible, but the risk gets increases upon the time fixed for reaching the targeted amount. Secondly if it has to be reached in a short time then gambling is the only hope else try with other forms of trading and making use of fiat and bitcoin into different business. Second form of earning needs lot time to get the amount doubled.
Risk really increases with the time frame, less time higer risk, more time lower risk. And that is conclusion of this questiom how to double amount OP mentioned. Choosing faster ways like gambling, daily trading, stocks is very risky, real estates, some sorts of saving and investing in bitcoin are long term, and with smaller risk amount can be doubled.
From all this gambling would be my choice, but not with all money, part of it, but with rest I would buy bitcoins and just wait.