You are given: Effective date of a decreasing annuity: 1/1/12. Date of the first payment: 7/1/12 Frequency of payments: Semiannually Number of payments: 20 Semiannually decrease in payment: $100 Interest rate: 5% per year, compounded semiannually Present value of remaining payments as of 1/1/18 (after 1/1/18): $30000 Calculate the first semiannual payment X. You are given: Effective date of a decreasing annuity: 1/1/12. Date of the first payment: 7/1/12 Frequency of payments: Semiannually Number of payments: 20 Semiannually decrease in payment: $100 Interest rate: 5% per year, compounded semiannually Present value of remaining payments as of 1/1/18 (after 1/1/18): $30000 Calculate the first semiannual payment X