Radu invested in shares of four different companies at the beginning of the year. At the end of the year the share values had increased or decreased as follows: Second Time Around Clothing 8.69% DigiCom 5.81% Echo Systems Stiller Co. -5.91% 8.28% For full marks your answers should be given as percents accurate to at least two decimal places. 

a) What is the total rate of return if Radu invests the same amount in each company? Return = 0.00 % 

b) What is the total rate of return if Radu invests four times as much in Second Time Around Clothing as in the other companies? Return = 0.00 %