question about iv calculations

On the bonus quiz #2 question #10. Can you explain how to do that.

An IV Drip is ordered to run at 4 gtt/min. It contains 875 mg of a drug in a 250 ml solution. How many mg will the patient receive per hour if the infusion set is calibrated to deliver 12 gtt/ml?

a. 0.70mg/hr

b. 16mg/hr

c. 70mg/hr

d. 160mg/hr

(by Keith)

The way I would do it is to first write down the factors.

Then I want to know how many drips will drop in one hour.

4gtt/min X 60 Min. = 240 gtt/hour

Next, I want to know how many ml that is.

Since each 12 gtt's adds up to 1 ml, I divide my total gtt / per hour by how many equal one 1 ml.

240 gtt/hr ÷ 12 gtt / ml = 20

That means that
20ml will drop each hour

Now, I want to know how many mg of the drug is in
20 ml.

So, take the known concentration and bounce 20 ml off of that to find out your answer. (
proportion math)

875mg                  X
  ------        =      -----

250ml             20ml

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