Which expression correctly gives the volume in liters when Flow Rate is in liters per minute and Time is in minutes?

• A. Flow Rate (L/min) / Time (min) = Volume in liters
• B. Time (min) * Flow Rate (L/min) = Mass (kg)
• C. Flow Rate (L/min) * Time (min) = Volume in kilograms
• D. Flow Rate (L/min) * Time (min) = Volume in liters

Answer: (D)

Volume comes from flow rate multiplied by the duration because flow rate is the amount of volume passing per unit time. If you multiply by how long that flow continues, you get the total volume that has flowed. The units confirm this: liters per minute times minutes equals liters, so you end up with volume in liters.

Dividing flow rate by time would not give a volume (it would yield a rate-like unit, L/min^2). Multiplying time by flow rate but labeling it as mass is incorrect because mass requires density to convert from volume to mass. And while flow rate times time does produce liters, it does not convert to kilograms without density, so the phrasing that it equals mass is wrong.