Here is the problem and the answers to my problem. I need help understanding how he got the 2 last parts of the journal. I put them in bold so you know which ones im talking about. I dont know how my instructor got the numbers and the number of months from in those 2 parts.

E8-14 Vandiver Company had the following select transactions.

Apr.	1, 2019	Accepted Goodwin Company's 12-month, 6% note in settlement of a $30,000 account receivable.
July	1, 2019	Loaned $25,000 cash to Thomas Slocombe on a 9-month, 10% note.
Dec.	31, 2019	Accrued interest on all notes receivable.
Apr.	1, 2020	Received principal plus interest on the Goodwin note.
Apr.	1, 2020	Thomas Slocombe dishonored its note; Vandiver expects it will eventually collect.

Instructions

Prepare journal entries to record the transactions. Vandiver prepares adjusting entries once a year on December 31.

Journalize entries for dishonor of notes receivable.

EXERCISE 8-14

4/1/19 Notes Receivable.................................................. 30,000

Accounts Receivable............................................... 30,000

7/1/19 Notes Receivable.................................................. 25,000

Cash.......................................................................... 25,000

12/31/19 Interest Receivable................................................. 1,350

Interest Revenue

($30,000 X 6% X 9/12)........................................... 1,350

Interest Receivable................................................. 1,250

Interest Revenue

($25,000 X 10% X 6/12)......................................... 1,250

4/1/20 Help with this one Cash................................................................. 31,800

Notes Receivable..................................... 30,000

Interest Receivable.................................. 1,350

Interest Revenue

($30,000 X 6% X 3/12).......................... 450------ I dont know how he got 3/12 when in the question it states "12 month note"

Help with this one Accounts Receivable...................................... 26,875

Notes Receivable..................................... 25,000

Interest Receivable.................................. 1,250

Interest Revenue

($25,000 X 10% X 3/12)........................ 625 ----------I dont know how he got this one either