You have $100,000 to invest in an equity portfolio. Your choices are Equity A with an expected return of 15%. Equity B with an expected return of 20%. Equity C with an expected return of 17% and equity D with an expected return of 11%. If you want to invest $20,000 at equity A and S35,000 at equity B, how much should you invest at Equity C and Equity D, so that your portfolios expected return will be 16%?