You own three stocks: $600$ shares of Apple Computer, $10,000$ shares of Cisco Systems, and $5,000$ shares of Colgate$-$Palmolive. The current share prices and expected returns of Apple, Cisco, and Colgate$-$Palmolive are, respectively, $$530,$ $$16,597$ and $12\%,10\%,8\%.$

a$.$ What are the portfolio weights of the three stocks in your portfolio?

b$.$ What is the expected return of your portfolio?

c$.$ Suppose the price of Apple stock goes up by $$20,$ Cisco rises by S$6,$ and Colgate$-$Palmolive falls by $$13.$ What are the new portfolio weights?

d$.$ Assuming the stocks' expected returns remain the same, what is the expected return of the portfolio at the new prices?