If a drip rate is 60 mL/hour for 2.5 hours, what is the total volume?

• A. 100 mL
• B. 150 mL
• C. 180 mL
• D. 200 mL

Answer: (B)

Infusion volume comes from multiplying the drip rate by the time the infusion runs. With a rate of 60 mL per hour for 2.5 hours, multiply 60 by 2.5. That gives 150 mL.

You can see it by breaking down the time: 2 hours at 60 mL/hour yields 120 mL, and half an hour at 60 mL/hour yields 30 mL. Add them together and you get 150 mL.

The other totals would require different times (for example, 180 mL would occur with 3 hours, and 200 mL with about 3.33 hours), so 150 mL fits the given rate and duration.