Final Answer:
The nurse should set the manual IV infusion to deliver 31.25 drops per minute.
Step-by-step explanation:
To calculate the infusion rate in drops per minute (gtt/min), you can use the formula:
After calculating, the infusion rate is found to be 31.25 drops per minute. Therefore, the nurse should set the manual IV infusion to deliver approximately 31.25 gtt/min to achieve the prescribed infusion rate of 125 mL/hr using the given 0.9% sodium chloride solution and the specified drop factor.