pharmacy question

by Mike
(San Marcos, Tx, USA)

They give
penicillin G potassium
250,000 U/kg/day up to 20,000 U
patient weighs 160lbs
iv administered over 24hr
20000000 U/L

and the question is how many milliliters will you need to extract from the 20,000,000 U/L iv bag of penicillin G potassium and what will be the resultant volume?

They don't give any examples on how to solve this in my book. I don't even know if this is the kind of question you can answer. But any help would be great. i know how to do all the conversion of units. Its just how to figure out how much to extract and the volume.