How are loan payments affected by interest rates? Is a loan amortisation table necessary?

Timothy borrowed $ Y from the bank for 25 years, servicing this loan with monthly payments of $Z, with the first payment being made one month after the loan. The nominal interest rate is 6% per annum, compounded monthly. Ifthe interest portion of the 8th payment is $1250, the value of SZ is closest to: (B) (C) (D) (E) $1,610 $1,627 $1,682 $1,708 $1,725