Explanation:
The determination of the maturity date and the interest for each notes is as follows
Contract date Maturity Month Maturity Date Interest expenses
March 19 May 18 $280
May 11 August 9 $660
October 20 December 4 $105
For March 19, the interest expense calculation is
= $28000 × 6% × 60 days ÷ 360 days
= $280
For May 11, the interest expense calculation is
= $33,000 × 8% × 90 days ÷ 360 days
= $660
For October 20, the interest expense calculation is
= $21000 × 4% × 45 days ÷ 360 days
= $105