For winners of the California SuperLotto Plus the choice is between a lump sum and annual pay- ments that increase from 2.5% for the first year, to 2.7% for the second year, and then increasing by .1% per year to 5.1% for the 26th payment. The lump sum is equal to the net proceeds of bonds pur- chased to fund the 26 payments. This is estimated at 45% to 55% of the lump sum amount. At what interest rate is the present worth of the two pay- ment plans equivalent if the lump sum is 45%? If it is 55%?