Helen Martin made an investment of $25,860.74. From this investment, she will receive $3,400 annually for the next 15 years starting one year from now. Click here to view the factor table. (For calculation purposes, use 5 decimal places as displayed in the factor table provided.) What rate of interest will Helen's investment be earning for her? (Hint: Use Table 4.) (Round answer to 0 decimal places, eg. 25%.) Rate of interest %