Answer:
0.8 mL.
Explanation:
You need to know that the equivalence in mcg to mg is 1000 mcg are 1 mg; so 500 mcg are 0.5 mg. Now you know that there are 0.5 mg per 2 mL, so if you divide all by 2, you will know that you have 0.25 mg per mL. Now you applied a rule of three: ((0.2 mg)(1 ml))/(.25 mg) = 0.8 mL. So the nurse need to administer 0.8 mL to provide 0.2 mg of dose.
