Answer:arithmetic average annual return per year= 3.75%
Explanation:
Year 1 = 10%
Year 2= 15%
Year 3 = 15%
Year 4 = -25%
total return = 15%
Arithmetic average annual return per year =(Return of year1 + return of year 2 + return of year 3+ return of year 4 )/4 = 15% /4 = 3.75%