Darryl and David are both 30 years old. Annuity A pays 1 per year as long as exactly one of the men is alive. Annuity B pays 3 per year while Darryl is alive, and 2 per year to David after Darryl dies. Annuity A has present value 8.50 and Annuity B has present value 32.25. Find the present value of an annuity paying 1 per year while both Darryl and David are alive.