Mr Tile Company purchased merchandise on account from a supplier for $9,000, terms 2/10, n/30. MR Tile

Question:

Mr Tile Company purchased merchandise on account from a supplier for $9,000, terms 2/10, n/30. MR Tile Company returned $1,500 of the merchandise and received full credit.
a. If MR Tile Company pays the invoice within the discount period, what is the amount of cash required for the payment?
b. Under a perpetual inventory system, what account is credited by MR Tile Company to record the return?