4. A stock market contains 30 stocks, each with annual volatility (standard deviation of the return) =0.15 and the pairwise correlation coefficient of the return is 0.2. Anson and Beth are holding some stocks in this market. It is known that: - Anson is holding twice the number of stocks held by Beth. - Beth's portfolio return variance is 20% larger than (i.e., 1.2 times of) Anson's portfolio. - Each person is holding an equally-weighted portfolio (in terms of the amount invested in each stock). Calculate the number of stocks held by each investor