Does someone has any suggestions how to make 17 BTC with 7 BTC starting capital in short period of time?
I think that you can try to gamble with them because that can earn you some quick Bitcoin but the chance of winning is not big so now what can happen if it goes wrong.
If you do not want to do that then you would have to use your own money.
Yeah best thing to do is to buy the other ten if possible because it is going to be a hard task to try and earn the other once in a free way.
I do not suggest gambling because gambling is just going to make you lose your Bitcoin.
Gambling is not the right place to invest that huge amount so I think better choice would be to invest in altcoins and start trading with it and over a period of time it will help you in growing your coins.