Answer:
9/40 hours, or 0.225 hours depending on how you have to answer
Explanation:
Find a common denominator, which would be 45. 1/5 * 9 = 9/45 inches/hour, 8/9 = 40/45 inches, to find how many hours it has been you divide 9/45 by 40/45, (9/45)/(40/45)=/225, or 9/40