I know most of journal entries except the last one on Jan1 2019. How does interest income is 43575???? I cant get this number. And why we need to have interest receivable on April 30 2018?

On January 1, 2018, The Founder Company received a 4-year promissory note that had a face value of $875,000 and a stated interest rate of S%, Interest was receivable on January 1 each year. The note was issued to yield an effective interest rate 0,8%. The Founder Company is publicly traded, uses the emave neet method of amortization for discounts or premiums, and has an April 30 year-end. Click here to view the factor table present value of to view factor table present value of an annuity of Credit Date Account Titles and Explanation January 1, Debit 2018 Notes Receivable 817,038 Cash 817,038 April 30, 2018 Interest Receivable 17,500 Notes Receivable 4,288 Interest Income 21,788 January 1, 2019 Cash 52,500 otes Receivable 8,575 Interest Receivable 17,500 Interest Income 43,575