This is Actuarial Science. Please help explain!

Problem 1 - Annuities in Arithmetic Progression Find the PV of a 24-year annuity-immediate with payments of 1, 2, 3, ..., 24 at an annual effective rate of interest i=7%.

PV=

6.

At an annual effective rate of interest i=7%, find the PV of the following annuities: A 13-year annuity-immediate with payments of 13, 12, 11, ..., 1. PV= A 13-year annuity-immediate with payments of 39, 36, 33, ..., 3. PV=

10.

Problem 10 - Annuities in Arithmetic Progression Find the PV of a perpetuity-immediate with payments of 1 in year 1, 2 in year 2, 3 in year 3, ..., and 23 in year 23. After 23, the payments remain constant at 23. The annual effective rate of interest i=4%. PV=