Dosage calculation help!!

  1. Hello All....I have a test on Tuesday, and I need help with setting up these problems...I can understand every other problem except these...Please help me with the easiest way to convert and set up the information...Thanks for your help.

    12. 100 mg of Nitroprusside has been added to D5W. The final solution has a volume of 250 mL. You realize that the IV solution contains___ mg of Nitropusside per mL.

    and also,

    13. An IV of D5W containing 40mg of Dopamine and a total volume of 50mL is to be infused at a rate of 25mcg/min. At how many mL/hr will you infuse the IV?

    ****these are the types of problems that I am having trouble setting up, I just want to know how I should put them into a formula....Thanks again.