X owns a perpetuity that will pay $1,500 a year, starting one year from now and will grow at 2 percent each year. He offers to sell you all of the remaining payments after the next 25 payments have been paid. He is willing to sell you the payments starting year 26 if you agree to pay him half the value today and half of it upon transfer in year 25. Assuming a discount rate of 8 percent how much would you pay him today and how much in year 25?

The answer is $2,994.47 today and $20,507 in year 25. Please explain how the answer was derived.