Calculate the portfolio risk for the selected stock pairing

Cobie is evaluating her portfolio performances. She currently has two stock (Stock BD and Stock CL) in her portfolio which she acquired 6 months ago. She notices that the correlation coefficient of her portfolio are almost perfectly positive thus she is considering to remove Stock CL from her portfolio. Furthermore, stock CL is continuously having a drop in its value. The potential replacement is Stock AM. Cobie downloaded the last five days' data of Stock AM to help in her decision. Date 1/7/2020 2/7/2020 3/7/2020 4/7/2020 5/7/2020 Open 2.20 2.50 3.00 4.20 3.78 Stock AM (in RM) Close 2.50 3.00 4.20 3.78 5.67 7 Matric no: Section: FIN4020 She also observes that her current portfolio is having the following information: Date Rates of return (ri) (in %) Stock BD Stock CL 1/7/2020 2/7/2020 10 -20 3/7/2020 5 -10 4/7/2020 20 5 5/7/2020 15 -5 Number of units owned 10,000 10,000