The total amount that should be debited to patents through July 31, 2017 is $210000. Hopson Company spent $120000 in legal fees for a patent that was granted on January 2, 2017 and on July 31, 2017, the company paid $90000 for legal fees in a successful defense of the patent. If combined, $120000 plus $90000, the total amount is $210000.