Given:
Ratio of ounces of oil to gallons of gasoline = 9 : 11
Gallons of gasoline = 55 gallons
Let's find the ounces of oil.
To find the ounces of oil, we have the equation:

Thus, we have:

Let x represent the ounces of oil.
Cross multiply:

Therefore, there are 45 ounces of oil.
ANSWER:
45 ounces of oil