Help with Math!!!

Im having some trouble doing this math can anyone explain to me how to do it? Thanks Im so lost right now
1.) The patient is ordered 8 ml of Ranitidine by mouth. It is available as 15 mg in 1 ml. How much medication is the patient receiving with each dose?
2.) Ampicillin 1 gram is ordered IV bid. It is available as 1 gram in 50 ml. The drug text states to run it over 30 minutes. The patient has 100 ml of NS via a primary line. The primary line is 60 gtts/ml, the piggyback tubing available is 15 gtts/ml. How many drops per minute should the IV Ampicillin run at?
thanks all, i cant figure these out 

Jun 13, '09the patient is ordered 8 ml of ranitidine by mouth. it is available as 15 mg in 1 ml. how much medication is the patient receiving with each dose?
1 : 15 = 8 : x
x = 120
you can also solve this using dimensional analysis if you prefer.
8 ml x (15 mg / 1 ml) = 120 mg
ampicillin 1 gram is ordered iv bid. it is available as 1 gram in 50 ml. the drug text states to run it over 30 minutes. the patient has 100 ml of ns via a primary line. the primary line is 60 gtts/ml, the piggyback tubing available is 15 gtts/ml. how many drops per minute should the iv ampicillin run at?
(50 * 15) / 30 = 25 drops/minute
i hope this helps. 

Jun 14, '09I know you already got your question answered, but I want to recommend a resource to you.
Math for Nurses is a book that my school required, and it was a great help! I have strong algebra skills (it does review those a lot if you need the help!) but found it very helpful for the multilevel conversions and the problems that involve drops (gtt) and oz to ml.
http://www.amazon.com/MathNursesPo.../dp/0781753724
Amazon has it for $22 but also has used copies for about $2.50. Well worth it!
Just a heads up, I did find a few errors in the answer key. (I let the author know and she was surprised and thankful to know!) I say this not to dissuade you from buying this book, but just to say that if you keep trying a problem and get the wrong answer a bunch of times in a row to try another one of the same type and see if you can get that one right instead of beating yourself up trying the same one over and over since the key may be off.