A student titrating a sample of a powdered aspirin tablet to find out how much acetylsalicylic acid is in the sample finds that it requires 15.5 mL of a 0.109 M sodium hydroxide solution to neutralize the acid in the sample. How many milligrams of acetylsalicylic acid did the sample contain? Use the correct number of significant figures and do not include units or your answer will be counted wrong.