At 0800 h, one litre of dextrose 4% and 1/5 normal saline is set to run at 75 mL/h. At what time would the bag be finished?

At 0800 h, one litre of dextrose 4% and 1/5 normal saline is set to run at 75 mL/h. At what time would the bag be finished?

• A. 2100 h
• B. 2230 h
• C. 2320 h
• D. 2120 h

Answer: (D)

The key idea here is to use Time = Volume ÷ Flow rate. The bag’s total volume is 1 liter (1000 mL). At a rate of 75 mL per hour, the time to finish is 1000 ÷ 75 = 13.333 hours, which is 13 hours and 20 minutes. Starting at 08:00, add 13 hours and 20 minutes and you reach 21:20 (9:20 PM). So the bag finishes at 21:20 h. If the total volume were 1.2 L, the finish would be later (around midnight), which isn’t listed, so the 1 L interpretation fits the given answer.

The key idea here is to use Time = Volume ÷ Flow rate. The bag’s total volume is 1 liter (1000 mL). At a rate of 75 mL per hour, the time to finish is 1000 ÷ 75 = 13.333 hours, which is 13 hours and 20 minutes. Starting at 08:00, add 13 hours and 20 minutes and you reach 21:20 (9:20 PM). So the bag finishes at 21:20 h. If the total volume were 1.2 L, the finish would be later (around midnight), which isn’t listed, so the 1 L interpretation fits the given answer.