What were the calculations that were done to get these debit and credit amounts? (Like how did they get 8,000 for premium bonds payable etc.)

On January 1, 2018, Alan Unlimited issues 14%, 20-year bonds payable with a face value of $160,000. The bonds are issued at 105 and pay interest cember 31. (Assume bonds payable are amortized using the straight-line amortization method.) Read the requirements. Requirement 1. Journalize the issuance of the bonds on January 1, 2018. (Record debits first, then credits. Select explanations on the last line of the journal entry.) Date Accounts and Explanation Debit Credit 2018 Jan. 1 168,000 Cash Premium on Bonds Payable Bonds Payable 8,000 160,000 Issued bonds at a premium. Requirement 2. Journalize the semiannual interest payment and amortization of bond premium on June 30, 2018. (Record debits first, then credits. Select explanations on the last line of the journal entry.) Date Accounts and Explanation Debit Credit 2018 Jun. 30 Interest Expense 11,000 Premium on Bonds Payable Cash 11,200 200) Paid semiannual interest and amortized premium. Requirement 3. Journalize the semiannual interest payment and amortization of bond premium on December 31, 2018. (Record debits first, then credits. Select explanations on the last line of the journal entry) Date Accounts and Explanation Debit Credit 2018 Dec. 31 Interest Expense 11,000 Premium on Bonds Payable Cash 200 11,200 Paid semiannual interest and amortized premium. Requirement 4. Journalize the retirement of the bond at maturity, assuming the last interest payment has already been recorded. (Give the date.) (Record debits first, then credits. Select explanations on the last line of the journal entry.) Date Accounts and Explanation Debit Credit 2037 Dec. 31 Bonds Payable 160,000 Cash 160,000 Retired bonds payable at maturity