Suppose that a sodium pentobarbitol is used to anesthetize a dog. The dog is anesthetized when its bloodstreams contains at least 45 milligrams of sodium pentobarbitol per kilogram of the dog's body weight. Suppose also that sodium pentobarbitol is eliminated exponentially from the dog's bloodstream, with a half life of 5 hours. What single dose should be administrated in order to anesthetize a 30-kg dog for 1 hour ?