A money manager is managing the account of a large investor. The investor holds the following stocks:

Stock Amount Invested Estimated Beta

A $2,000,000 2.80

B 5,000,000 1.70

C 3,000,000 1.40

D 5,000,000 ???

The portfolios required rate of return is 12 percent. The risk-free rate is 3 percent and the total return on the market portfolio is 8 percent. What is Stock Ds estimated beta?

please help with excel step-by-step (detailed) much appreciated.