Sold merchandise on account for 30,000 terms FOB1/10, n/30. The cost of merchandise sold at was 19,500. How much cost of merchandise sold and merchandise inventory?

The COST of the merchandise was given in the problem.

If it's sold, it's no longer in inventory. There isn't any way to know what is left in inventory. If you are trying to paraphrase what the problem is asking, I would suggesting writing it exactly as it was written, because I'm not sure what you're needing to know there.

Debit COCS (an expense account)
Credit Inventory (an Asset account

The amount is given