Interest rate (with changing years). Keiko is looking at the following investment choices and wants to know what annual taile of rehirt each choice producos a. Invest $42000 and receive $774.637 in 8 years b. Invest $3,300.00 and teceive $10.449.11 in 17 years c. Invest $32,70379 and receive $130,00000 in 20 years d. Invest $31,48276 and receive $1,300,00000 in 30 years. a. What annual rate of retum will Keiko eam if she invests 5420.00 today and receives 517463 in 8 years? K (Round to two decintal places.)