You have orders to give a patient 20 mg of a certain medication. the medication is stored 4 mg per 5-ml dose. how many milliliters will need to be given

Set up a proportion to solve.
(4mg/5ml)= (20mg/x ml)
Be sure you line up the mg to mg and the ml to ml.
Notice I have both mg on the numerator and both ml on the denominator.
To solve you need to cross multiply.
4x = 5(20)
4x = 100
divide by 4
x = 25 ml

I hope this helps. :-)