Investing 0.1 in your own busniss and try to earn 100 btc is a dream and if you invest in someone else busniss and risk them is not a good idea you need to work with your own money not give them and risk for a scam
Their is no point when you know winner would be just 1 and not many and out of thousand of entry if you see % it is negligible . Hence probability of you winning is not much to risk those 0.1 btc. Instead I am sure if I invest now this in some coins as market is down I would get much better returns and can easily double in coming month mostly.