Need with formula

23) The Dickerson PR Firm is considering two mutually excluasive pro of 3 and 6 years. The after-tax cash flows for projects with useful lives S and L are listed below -$60,000 40,000$1500100 19,000 320,00013,000 11,000 20,000 Assume a required return of 15%. (5 points) a) Wh b) What is the equivalent annual annuity for each projeet? c) Which project should Dickerson choose based on the EAA method? at is the net present value for each project