Calculate amount of IV fluid to be added to the volume control chamber.

Ordered:D5W at 30 mL/hr for continuous infusion with medication x 60 mg every 6 hours to be infused over 20 minutes by volume control set

On hand:Medication x 60 mg/2 ml
The book says 8 mL but I'm getting everything but that. I need an easier formula to go by so I can learn this for future similar problems.