What to do if some expertise messaged you That they did work for you??

Hye! Steemians Family, i don't know much about trade but few days ago a person sent me a message and say hello to me i just said hello and ask him who are you? He said that i m a professional trader and manage accounts and i will manage your account too. I asked him i want to start a trade with $300 so what it will worth to me? he Said that i will manage your account and give you $4800 a weekly profit and i will take 10% and you will get 90% profit .
The reason behind sharing this story to know that its a scam or real to earn $4800 weekly with $300 deposit??
and if he is a professional so why he trade for me? why he not trade with his money?? he said that he have a 99% win strategy ??
here is the screenshot of message can any one help me to solve this puzzle??