250,000(1+i)^15 = 51,200((1+i)^15 -1)/i)

solve for i.

Is there a simple step I'm missing to make solving for i easier??

(this comes from setting two future value equations equal to one another to determine at what interst rate a lifetime annuity = a lump sum...

FV=PV(1+i)^n=PMT((1+i)^15 -1)/i) where PV = the lump sum of 250,000 and PMT = lifetime annuity of 51200 and i is the interest rate). The answer is 24.83% (thanks to trial and error), but I am trying to get there algebraically...

THANKS for any ideas!