Find a solution for this math problem: Alex needs to be 54 inches tall to ride the newest roller coaster at the theme park. He is 48 inches tall this year. He hears a rumor that for every hour he hangs upside down, he can grow 1/12 of an inch. Normally he grows 1/3 of an inch per month. On average, how many hours does he need to hang upside down each month to be tall enough next year to ride the rollercoaster?