With that amount of investment you have only 2 choices to make either you go for altcoin investment or else try your luck in gambling and if you are lucky then you can double your investment even in a single day so you can choose according to the risk that you can afford to take.
Gambling is not the good option if you want to double your investment because it is highly risky and mostly people loose their capital here on gambling, trading is better option to increase your coins though it is also risky but if you done a survey of market before investing then you will get some good profit.
agree gambling its not a good choice if you choose gambling they have possible that your bitcoin loss. The chances of winning is very low while the chances of loss is very high. I think investing in altcoin is thr good option you buy altcoin with cheap price and then hold for a few weeks or maybe a month for sure you will earn profit if you do that.