Drip rate is 40 mL/hour for 3.5 hours. What is the total volume to be infused?

• A. 80 mL
• B. 40 mL
• C. 140 mL
• D. 280 mL

Answer: (C)

Calculating total fluid infused comes down to multiplying the infusion rate by the time the infusion runs. With a rate of 40 mL per hour for 3.5 hours, multiply 40 by 3.5 to get the volume: 40 × 3.5 = 140 mL. You can see it as 3 hours contributing 120 mL (40 × 3) plus 0.5 hours contributing 20 mL (40 × 0.5), totaling 140 mL. Since rate (mL/hour) times time (hours) gives a volume (mL), the units line up correctly. So the total volume to be infused is 140 mL. The other values correspond to different times (e.g., 2 hours would yield 80 mL, 1 hour would yield 40 mL, 7 hours would yield 280 mL) and don’t match the given 3.5 hours.