# Formula (Pharmacy) Math

by Heidi
(Texas)

You have a 15g vial of medication with instructions to add 34.9mL to have a concentration of 375mg/mL.

What is the powder volume in the vial?

A. 5.1 mL
B. 8.7 mL
C. 30.9 mL
D. 40 mL

### Comments for Formula (Pharmacy) Math

 Answer by: Anonymous 15000mg/375mg = 40mL - 34.9mL = 5.1mL Answer. A

 Math by: Huma I don't like formulary math like this. But, what we can do? We have to learn it all. It calls for powder drug preparation calculation. Remember two kinds of question: 1)what is the powder volume ? 2)What will be the concentration of the drug after reconstitution ? etc...

 question by: Anonymous convert 400 mcg to milligrams

 Is this right? please help! by: Anonymous I get 40 for the answer!!!!Is this right?15000mg_______= 40mg375 mg

 additional comments by: Anonymous 40 is the total volume 40-34.9= powder (dry)Just remember when you set up your equation the answer to the equation ie: 'x' is not the answer to the problem. You need to subtract the liquid 34.9 to get thepv or powder volume.

 student by: Anonymous 1.5g/34.9 =375/xml then cross multiply u get 13087.5/1.5g then change gram into milligram u get 15oo then divide 13087.5/1500 =8.725 and that is answer