Sales Tax

Hello
The question is from F3 BPP REVISION KIT.
Topic: Sales tax
Question no. 5.2

The following information relates to EVA Co’s sales tax for month of March 20X3:

Sales (including sales tax) $109,250
Purchases (net of sales tax) $64,000

Sales tax is charged at a flat rate of 15%. Eva Co’s sales tax accounts showed an opening credit balance of $4,540 at the beginning of the month and a closing debit balance of $2,720 at the end of the month.

What was the total sales tax paid to regulatory authorities during the month of march 20X3?

( I have looked at the solution and what confused me is that there is a posting of c/d $2,720 on the credit side of the T account, where as it clearly says “a closing debit balance of $2,720 at the end of the month.” in the question.

Can somebody please explain to me conceptually why was the c/d balance posted on credit side. THANK YOU)