please show all work

answer number 8 show all work please

7. (10 pts) Given the force of interest is , find the present value at time 0 of 5+1 $700 to be paid at time t = 4. 8. (10 pts) Abby deposits $600 in an account that grows by compounding interest. a. After five years her account has a balance of $2000. Assuming there is a constant annual effective rate find the rate. b. Find the tripling time if the rate if interest rate is 4%. 8. (10 pts) Abby deposits $600 in an account that grows by compounding interest. a. After five years her account has a balance of $2000. Assuming there is a constant annual effective rate find the rate. b. Find the tripling time if the rate if interest rate is 4%