(Annuity interest rato) Your folks just called and would tike some advice from you. An insurance agent just called them and offered them the cpportunity to purchase an annulty for $25,820. 39 that wil pay them $3,500 per year for 15 yean. They dont have the slightest idea what retum fhey would be making on their imestment of $25,820.39. What rate of roturn would they be earning? The ancual rate of retum your folis would be earring on their investment is 4. (Round to two decimal places )