Revenue Recognition – interest prob

https://becker-atc.com/wp-content/uploads/2014/05/F7INTFR-Study-Question-Bank_Sample_D14-J15.pdf.

Question 15 – Jenson pg-10. Answer pg: 1022
Year end: 31 Mar
In the first item, the goods were sold at 1 June (10 months to year end). The sales actually being a loan, should be accounted for in the St. of Fin Pos as Loan in Non current liabilities. The interest being 10% should be 3500 (35000*12%=4200- apportioned on 10 months=3500)
In the answer they’ve considered only 9 months worth of interest ie. 3150.
Plz explain