I guess I could always open a second trading account which would keep the funds separate, however, this would be a bit of a pain having to sign in and out of multiple accounts.
Thanks.
Edit: Just so everyone knows, a close friend of mine has asked me to trade with some of their money. They have witnessed my trading and know that I am profitable. It is NOT a random person as others have suggested on this thread. Either way this does not matter and I would like to keep the discussion on topic.
This is the solution to supporting someone who is a trader and isn't making profit or someone who has the desire to invest with you. Open a separate account for the individuals if you are willing to trade for them.
The pain of signing in and out of accounts is fairer than the pain of endless and stressful calculation of percentage of profit or loss of a joint account.