A deposit of 800 is made into a fund at time 0. The fund pays interest at a nominal rate of discount, k compounded semiannually for the first three years.

After that, interest is credited at a force of interest, t=1t+1t=1t+1.

At the end of five years, the accumulated value of the fund is 1,500.

Calculate k.

1. 7.3%

2. 7.6%

3. 7.9%

4. 8.2%

5. 8.5%