EXPLANATION
We need to multiply the number of needed milligrams by the weight of the patient, but first turning the weight in lbs into kilograms,
[tex]?Kilograms=165lbs*\frac{0.453}{1lb}=74.745Kg[/tex]Now, multiplying the obtained weight by the number of miligrams, give us the dose:
[tex]Dose=40\frac{mg}{Kg}*74.745Kg=2989.8mg[/tex]In conclusion, the nurse should give 2989 mg of the drug.