HK Ltd$.$ borrowed $$1,000,000$ from Bank D and paid $$90,000$ in interest on this loan during the current year. The loan was secured by a fixed deposit in the amount of $$500,000$ placed outside Hong Kong and a director$$s personal guarantee. The deposit earned $$30,000$ in the current year. There was no other security. In the year of assessment, HK Ltd$.$ earned tax$-$free interest of $$30,000$ from the deposit and paid interest of $$90,000$ on the loan to Bank D$.$ How much interest expense can HK Ltd$.$ deduct?