please give me correct answer.

4.(a) Prepare the following journal entry for Elon Co.: Sep 2: Elon Co. had purchased merchandise from Bezos Co. on account for $20,000 terms 2/10, n/30 before.

Sep 12: Paid the amount due to Bezos Co. in full.

(b) Buffet Clothing Store purchases each shirt for $10 and sells each shirt for $15. It sold 120 shirts during the month. If it had $400 admin & selling expense and no interest expense, then what was its gross profit and net profit for that month?