I'm sure a tutor will weigh in with the correct, clearer, more thorough solution... but, as you have calculated the return on the market portfolio, this return should be equal to the "weighted by market capitalisation" return of the individual assets. This is because CAPM hold and we are assuming the portfolio is efficient => the separation theorem holds.
The beta figures can be calculated from the expected return on the market and expected return on each asset:
E[asset] = r + beta(E[market] - r)
Chris
Last edited: Jul 24, 2014