Grouper Company issued $612,000 of 10%, 20-year bonds on January 1, 2020, at 102. Interest is payable semiannually on July 1 and January 1. Grouper Company uses the effective-interest method of amortization for bond premium or discount. Assume an effective yield of 9.7705%. Prepare the journal entries to record the following. (Round intermediate calculations to 6 decimal places, e. g. 1.251247 and final answer to 0 decimal places, e. g. 38,548. If no entry is required, select "No Entry" for the account titles and enter 0 for the amounts. Credit account titles are automatically indented when amount is entered. Do not indent manually.)
(a) The issuance of the bonds.
(b) The payment of interest and related amortization on July 1, 2020.
(c) The accrual of interest and the related amortization on December 31, 2020.

Bond issue:

Dr cash                               $624,240.00

Cr bonds payable                                                                       $612,000

Cr premium on bonds payable($624,240.00-$612,000)      $ 12,240

On 30 June:

Dr Interest expense                         $30,495.68  

Dr premium on bonds payable              $104.32  

Cr cash                                                                       $30,600

On 31 December :

Dr interest                                                                        $ 30,490.59  

Dr premium on bonds payable($30,600-$30,490.59)  $109.41

Cr interest payable                                                                             $30,600

Explanation:

The cash proceeds from the bond issuance is 102% of the face value of $612,000 i.e $ 624,240.00 (102%*$612,000)

The interest payment on 30 June=$612,000*10%*6/12=$30,600.00  

The interest expense on 30 June=$ 624,240.00*9.7705%*6/12=$30,495.68

amortization of premium=$30,600.00-$ 30,495.68=$104.32  

Carrying value of bond at 30 June=$ 624,240.00+$30,495.68 -$30,600=$624,135.68  

Interest expense on 31 December=$ 624,135.688*9.7705%*6/12=$30,490.59  

how does that happen,where u steel points