A physician orders 1500 mL of NS to infuse at 75 mL per hour. How many hours will this IV run?

A physician orders 1500 mL of NS to infuse at 75 mL per hour. How many hours will this IV run?

• A. 15 Hours
• B. 20 Hours
• C. 25 Hours
• D. 30 Hours

Answer: (B)

This question tests how to determine the duration of an IV infusion using time = volume ÷ rate. If you have 1500 mL to infuse at 75 mL per hour, divide 1500 by 75 to find the hours: 1500 ÷ 75 = 20. So the IV will run for 20 hours. A quick check confirms the math: 20 hours × 75 mL/hour = 1500 mL. The other options would deliver different total volumes in the given time (e.g., 15 hours would deliver 1125 mL, 25 hours would deliver 1875 mL, 30 hours would deliver 2250 mL).

This question tests how to determine the duration of an IV infusion using time = volume ÷ rate. If you have 1500 mL to infuse at 75 mL per hour, divide 1500 by 75 to find the hours: 1500 ÷ 75 = 20. So the IV will run for 20 hours. A quick check confirms the math: 20 hours × 75 mL/hour = 1500 mL. The other options would deliver different total volumes in the given time (e.g., 15 hours would deliver 1125 mL, 25 hours would deliver 1875 mL, 30 hours would deliver 2250 mL).