An investor wants to distribute their funds among three investments: Stocks, Bonds, and Real Estate. Each investment has different returns in terms of annual interest, risk factor, and liquidity. The investor wants to achieve a total annual interest of $$5000,$ a risk factor score of $15,$ and liquidity of $$10000.$ Each unit of investment in Stocks yields $$200$ annual interest, a risk factor of $3,$ and liquidity of $$4000.$ Each unit of investment in Bonds yields $$100$ annual interest, a risk factor of $2,$ and liquidity of $$3000.$ Each unit of investment in Real Estate yields $$300$ annual interest, a risk factor of $1,$ and liquidity of $$2000.$ How much should be invested in each to meet the investor's goals?